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Abstract: Whether mudflats are an important source of atmospheric ammonia (NH3) remains an open question, despite the fact that over half of the world's population live within 3 km of surface water bodies. Here, we established three sites (lake, river, and sea) that are representative of tide-influenced mudflats across the Yangtze Delta in eastern China. Online field measurements of NH3 and auxiliary hydrometeorological parameters were simultaneously performed over a 9 month period. Surprisingly, the average NH3 concentrations measured at these locations are as low as regional background levels. No pulses of increased NH3 were found at these sites when mudflats were exposed due to receding water levels. High atmospheric NH3 concentrations are persistently associated with high temperatures, but their geographical origins have no overlap with the locations of water bodies. The potential mechanism is also discussed. Collectively, we provide the first direct observational evidence concerning mudflat as a source of NH3 © 2020 American Chemical Society.
BibTeX:
@article{ChangClarisseVanDammeEtAl2020,
  author = {Chang, Y. and Clarisse, L. and Van Damme, M. and Tao, Y. and Zou, Z. and Dore, A.J. and Collett, J.L.},
  title = {Ammonia Emissions from Mudflats of River, Lake, and Sea},
  journal = {ACS Earth and Space Chemistry},
  year = {2020},
  volume = {4},
  pages = {614-619},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084654739&doi=10.1021%2facsearthspacechem.0c00017&partnerID=40&md5=b873319a4fd169e7896211e689362bd9},
  doi = {10.1021/acsearthspacechem.0c00017}
}
Abstract: Very fine silicate-rich volcanic ash, generated by explosive volcanic eruptions, can efficiently be traced downwind with infrared satellite sounders. Their measurements can also be used to derive physical parameters, such as optical depths and effective radii. However, one of the key requirements for accurate retrievals is a good knowledge of the complex refractive index (CRI) of the ash under investigation. In the past, the vast majority of the studies used the CRIs from Pollack et al. [Icarus 19, 372 (1973)], which are based on measurements of thin slices of volcanic rock, and therefore are not representative for airborne volcanic ash particles. Here, we report measurements of the CRI of volcanic ash in suspension, generated from samples collected from recent high-impact eruptions in Chile (Puyehue-Cordón Caulle, Calbuco, and Chaitén), Iceland (Eyjafjallajökull and Grímsvötn), and Italy (Etna). The samples cover a wide range of SiO2 content (46% to 76%) as confirmed by an X-ray fluorescence analysis. In the experimental setup, volcanic ash was suspended in nitrogen through mechanical agitation. Extinction spectra were recorded in the infrared, visible, and ultraviolet spectral regions. The particle size distribution within the airflow was also recorded. An iterative algorithm allowed us to obtain fully consistent CRIs for the six samples, compatible with the observed extinction spectra and the Kramers–Krönig relations. While a good agreement is found with other recently reported CRIs in the UV/Vis, larger differences are found in the longwave infrared spectral region. © 2020 Optical Society of America.
BibTeX:
@article{DeguinePetitprezClarisseEtAl2020,
  author = {Deguine, A. and Petitprez, D. and Clarisse, L. and Guđmundsson, S. and Outes, V. and Villarosa, G. and Herbin, H.},
  title = {Complex refractive index of volcanic ash aerosol in the infrared, visible, and ultraviolet},
  journal = {Applied Optics},
  year = {2020},
  volume = {59},
  pages = {884-895},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85078699302&doi=10.1364%2fAO.59.000884&partnerID=40&md5=eed947c336c2e5de943dc02931b5ec64},
  doi = {10.1364/AO.59.000884}
}
Abstract: Volcanic plumes can be transported across vast distances and can have an impact on solar ultraviolet radiation (UVR) reaching the surface due to the scattering and absorption caused by aerosols. The dispersion of the volcanic plume from the Puyehue-Cordon Caulle volcanic complex (PCCVC) eruption was investigated to determine the effect on aerosol loading at Cape Point, South Africa. The eruption occurred on 4 June 2011 and resulted in a plume reaching a height of between 9 and 12 km and was dispersed across the Southern Hemisphere. Satellite sulphur dioxide (SO2) observations and a dispersion model showed low concentrations of SO2 at the secondary site. However, satellite observations of volcanic ash and ground-based aerosol measurements did show increases between 10 and 20 June 2011 at the secondary site. Furthermore, there was good agreement with the dispersion model results and observations from satellites with most of the plume located between latitudes 40°-60° South. © 2020 by the authors.
BibTeX:
@article{DuPreezBencherifBegueEtAl2020,
  author = {Du Preez, D.J. and Bencherif, H. and Bègue, N. and Clarisse, L. and Hoffman, R.F. and Wright, C.Y.},
  title = {Investigating the large-scale transport of a volcanic plume and the impact on a secondary site},
  journal = {Atmosphere},
  year = {2020},
  volume = {11},
  article number = {548},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085914248&doi=10.3390%2fatmos11050548&partnerID=40&md5=29e07d8eba7566fb69b79a96badb00c2},
  doi = {10.3390/atmos11050548}
}
Abstract: Formic (HCOOH) and acetic acids (CH3COOH) are the most abundant carboxylic acids in the Earth's atmosphere and key compounds to aqueous-phase chemistry. Here we present the first distributions of CH3COOH retrieved from the 2007–2018 satellite observations of the nadir-looking infrared atmospheric sounding interferometer (IASI), using a neural network-based retrieval approach. A joint analysis with the IASI HCOOH product reveals that the two species exhibit similar distributions, seasonality, and atmospheric burden, pointing to major common sources. We show that their abundance is highly correlated to isoprene and monoterpenes emissions, as well as to biomass burning. Over Africa, evidence is provided that residual smoldering combustion might be a major driver of the HCOOH and CH3COOH seasonality. Earlier seasonal enhancement of HCOOH at Northern Hemisphere middle and high latitudes and late seasonal secondary peaks of CH3COOH in the tropics suggest that sources and production pathways specific to each species are also at play. ©2020. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{FrancoClarisseStavrakouEtAl2020,
  author = {Franco, B. and Clarisse, L. and Stavrakou, T. and Müller, J.-F. and Taraborrelli, D. and Hadji-Lazaro, J. and Hannigan, J.W. and Hase, F. and Hurtmans, D. and Jones, N. and Lutsch, E. and Mahieu, E. and Ortega, I. and Schneider, M. and Strong, K. and Vigouroux, C. and Clerbaux, C. and Coheur, P.-F.},
  title = {Spaceborne Measurements of Formic and Acetic Acids: A Global View of the Regional Sources},
  journal = {Geophysical Research Letters},
  year = {2020},
  volume = {47},
  article number = {e2019GL086239},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081079100&doi=10.1029%2f2019GL086239&partnerID=40&md5=9527069c499537594245ac724e1696e0},
  doi = {10.1029/2019GL086239}
}
Abstract: Atmospheric ammonia (NH3) is an alkaline gas and a prominent constituent of the nitrogen cycle that adversely affects ecosystems at higher concentrations. It is a pollutant, which influences all three spheres such as haze formation in the atmosphere, soil acidification in the lithosphere, and eutrophication in water bodies. Atmospheric NH3 reacts with sulfur (SOx) and nitrogen (NOx) oxides to form aerosols, which eventually affect human health and climate. Here, we present the seasonal and inter-annual variability of atmospheric NH3 over India in 2008–2016 using the IASI (Infrared Atmospheric Sounding Interferometer) satellite observations. We find that Indo-Gangetic Plains (IGP) is one of the largest and rapidly growing NH3 hotspots of the world, with a growth rate of +1.2% yr−1 in summer (June–August: Kharif season), due to intense agricultural activities and presence of many fertilizer industries there. However, our analyses show insignificant decreasing trends in annual NH3 of about −0.8% yr−1 in all India, about −0.4% yr−1 in IGP, and −1.0% yr−1 in the rest of India. Ammonia is positively correlated with total fertilizer consumption (r = 0.75) and temperature (r = 0.5) since high temperature favors volatilization, and is anti-correlated with total precipitation (r = from −0.2, but −0.8 in the Rabi season: October–February) as wet deposition helps removal of atmospheric NH3. This study, henceforth, suggests the need for better fertilization practices and viable strategies to curb emissions, to alleviate the adverse health effects and negative impacts on the ecosystem in the region. On the other hand, the overall decreasing trend in atmospheric NH3 over India shows the positive actions, and commitment to the national missions and action plans to reduce atmospheric pollution and changes in climate. © 2020 Elsevier B.V.
BibTeX:
@article{KuttippurathSinghDashEtAl2020,
  author = {Kuttippurath, J. and Singh, A. and Dash, S.P. and Mallick, N. and Clerbaux, C. and Van Damme, M. and Clarisse, L. and Coheur, P.-F. and Raj, S. and Abbhishek, K. and Varikoden, H.},
  title = {Record high levels of atmospheric ammonia over India: Spatial and temporal analyses},
  journal = {Science of the Total Environment},
  year = {2020},
  volume = {740},
  article number = {139986},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086632036&doi=10.1016%2fj.scitotenv.2020.139986&partnerID=40&md5=7b295822835cceb4839a787dc16239ef},
  doi = {10.1016/j.scitotenv.2020.139986}
}
Abstract: Husbandry trace gases that have climate change implications such as carbon dioxide (CO2), methane (CH4) and ammonia (NH3) can be quantified through remote sensing; however, many husbandry gases with health implications such as hydrogen sulfide (H2S), cannot. This pilot study demonstrates an approach to derive H2S concentrations by coupling in situ and remote sensing data. Using AMOG (AutoMObile trace Gas) Surveyor, a mobile air quality and meteorology laboratory, we measured in situ concentrations of CH4, CO2, NH3, H2S, and wind at a southern California university research dairy. Emissions were 0.13, 1.93, 0.022 and 0.0064 Gg yr−1; emission factors (EF) were 422, 6333, 74, and 21 kg cow−1 yr−1, respectively, for the 306 head herd. Contributing to these strong EF were spillway emissions from a grate between the main cowshed and the waste lagoon identified in airborne remote sensing data acquired by the hyperspectral thermal infrared imager, Mako. NH3 emissions from the Chino Dairy Complex, also in southern California, were calculated from Infrared Atmospheric Sounding Interferometer (IASI) satellite data for 2008–2017 using average morning winds, yielding a flushing time of 2.7 h, and 8.9 Gg yr−1. The ratio of EF(H2S) to EF(NH3) for the research dairy from AMOG data were applied to IASI NH3 emissions to derive H2S exposure concentration maps for the Chino area, which ranged to 10–30 ppb H2S for many populated areas. Combining remote sensing with in situ concentrations of multiple emitted gases can allow derivation of emissions at the sub-facility, facility, and larger scales, providing spatial and temporal coverage that can translate into exposure estimates for use in epidemiology studies and regulation development. Furthermore, with high fidelity information at the sub-facility level we can identify best practices and opportunities to sustainably and holistically reduce husbandry emissions. © 2019 Elsevier B.V.
BibTeX:
@article{LeiferMeltonTrattEtAl2020,
  author = {Leifer, I. and Melton, C. and Tratt, D.M. and Buckland, K.N. and Chang, C.S. and Clarisse, L. and Franklin, M. and Hall, J.L. and Brian Leen, J. and Lundquist, T. and Van Damme, M. and Vigil, S. and Whitburn, S.},
  title = {Estimating exposure to hydrogen sulfide from animal husbandry operations using satellite ammonia as a proxy: Methodology demonstration},
  journal = {Science of the Total Environment},
  year = {2020},
  volume = {709},
  article number = {134508},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077365894&doi=10.1016%2fj.scitotenv.2019.134508&partnerID=40&md5=952eaadd522b1553ad75df8945efc258},
  doi = {10.1016/j.scitotenv.2019.134508}
}
Abstract: Bogoslof volcano, Alaska, experienced at least 70 explosive eruptions between 12 December 2016 and 31 August 2017. Due to its remote location and limited local monitoring network, this eruption was monitored and characterized primarily using remote geophysical and satellite techniques. SO2 emissions from Bogoslof were persistently detected by the Infrared Atmospheric Sounding Interferometer (IASI) satellite sensors. Of Bogoslof’s 70 explosive events, 50% produced measurable SO2 masses ranging from 0.1 to 21.5 kt, with a median and standard deviation of 0.7 ± 4.0 kt SO2, respectively. Here, we compare IASI-derived SO2 masses from Bogoslof events to complementary geophysical datasets to provide insights into eruption source processes, namely the degree of seawater scrubbing of water-soluble SO2 and variations in magma flux. Correlations with the number of lightning strokes and infrasound energy are expected to indicate magma-flux as a controlling process, while correlations with infrasound frequency index are expected to indicate variations in vent-water content as a controlling factor. These comparisons suggest that the measured SO2 masses are primarily a function of eruption magnitude (degassed magma mass) and that scrubbing of SO2 emissions by vent seawater may have exerted a minor effect on the observed SO2 masses. SO2 masses were combined with petrologic constraints on melt inclusion and matrix glass S concentrations to calculate degassed magma masses and volumes. The cumulative SO2-derived degassed magma mass and estimated volume (dense-rock equivalent) for the full Bogoslof eruption were found to be 2.8 × 1010 kg and 9.3 × 106 m3, respectively. When individual event masses are compared against event masses calculated using an empirical plume-height method, a strong correlation is found (R2 = 0.83), with better than order-of-magnitude agreement in most cases. These estimates of eruption masses provide useful information on the magnitude, behavior, and associated hazards of the 2016–2017 eruption, and potentially future unrest at Bogoslof volcano. © 2020, International Association of Volcanology & Chemistry of the Earth's Interior.
BibTeX:
@article{LopezClarisseSchwaigerEtAl2020,
  author = {Lopez, T. and Clarisse, L. and Schwaiger, H. and Van Eaton, A. and Loewen, M. and Fee, D. and Lyons, J. and Wallace, K. and Searcy, C. and Wech, A. and Haney, M. and Schneider, D. and Graham, N.},
  title = {Constraints on eruption processes and event masses for the 2016–2017 eruption of Bogoslof volcano, Alaska, through evaluation of IASI satellite SO2 masses and complementary datasets},
  journal = {Bulletin of Volcanology},
  year = {2020},
  volume = {82},
  article number = {17},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85078328095&doi=10.1007%2fs00445-019-1348-z&partnerID=40&md5=1d20d4345eaae2ed99e74ffcb9037cf2},
  doi = {10.1007/s00445-019-1348-z}
}
Abstract: Air pollution and sea pollution are both impacting human health and all the natural environments on Earth. These complex interactions in the biosphere are becoming better known and understood. Major progress has been made in recent past years for understanding their societal and environmental impacts, thanks to remote sensors placed aboard satellites. This paper describes the state of the art of what is known about air pollution and focuses on specific aspects of marine pollution, which all benefit from the improved knowledge of the small-scale eddy field in the oceans. Examples of recent findings are shown, based on the global observing system (both remote and in situ) with standardized protocols for monitoring emerging environmental threats at the global scale. © 2020, The Author(s).
BibTeX:
@article{ViatteClerbauxMaesEtAl2020,
  author = {Viatte, C. and Clerbaux, C. and Maes, C. and Daniel, P. and Garello, R. and Safieddine, S. and Ardhuin, F.},
  title = {Air Pollution and Sea Pollution Seen from Space},
  journal = {Surveys in Geophysics},
  year = {2020},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086021035&doi=10.1007%2fs10712-020-09599-0&partnerID=40&md5=29a6493759621141b9dc2a20a09af169},
  doi = {10.1007/s10712-020-09599-0}
}
Abstract: The Paris megacity experiences frequent particulate matter (i.e.PM2:5, particulate matter with a diameter less than 2.5 μm) pollution episodes in spring (March.April). At this time of the year, large numbers of the particles consist of ammonium sulfate and nitrate which are formed from ammonia (NH3) released during fertilizer spreading practices and transported from the surrounding areas to Paris. There is still limited knowledge of the emission sources around Paris, their magnitude, and their seasonality. Using space-borne NH3 observation records of 10 years (2008.2017) and 5 years (2013.2017) provided by the Infrared Atmospheric Sounding Interferometer (IASI) and the Cross-Track Infrared Sounder (CrIS) instrument, regional patterns of NH3 variabilities (seasonal and interannual) are derived. Observations reveal identical high seasonal variability with three major NH3 hotspots found from March to August. The high interannual variability is discussed with respect to atmospheric total precipitation and temperature. A detailed analysis of the seasonal cycle is performed using both IASI and CrIS instrument data, together with outputs from the CHIMERE atmospheric model. For 2014 and 2015, the CHIMERE model shows coefficients of determination of 0.58 and 0.18 when compared to IASI and CrIS, respectively. With respect to spatial variability, the CHIMERE monthly NH3 concentrations in spring show a slight underrepresentation over Belgium and the United Kingdom and an overrepresentation in agricultural areas in the French Brittany.Pays de la Loire and Plateau du Jura region, as well as in northern Switzerland. In addition, PM2.5 concentrations derived from the CHIMERE model have been evaluated against surface measurements from the Airparif network over Paris, with which agreement was found (r2 = 0.56) with however an underestimation during spring pollution events. Using HYSPLIT cluster analysis of back trajectories, we show that NH3 total columns measured in spring over Paris are enhanced when air masses originate from the north-east (e.g. the Netherlands and Belgium), highlighting the importance of long-range transport in the NH3 budget over Paris. Variability in NH3 in the north-east region is likely to impact NH3 concentrations in the Parisian region since the crosscorrelation function is above 0.3 (at lag=0 and 1 d). Finally, we quantify the key meteorological parameters driving the specific conditions important for the formation of PM2.5 from NH3 in the Ile-de-France region in spring. Datadriven results based on surface PM2.5 measurements from the Airparif network and IASI NH3 measurements show that a combination of the factors such as a low boundary layer of ∼ 500 m, a relatively low temperature of 5 °C, a high relative humidity of 70 %, and wind from the north-east contributes to a positive PM2.5 and NH3 correlation. © 2020 Author(s).
BibTeX:
@article{ViatteWangVanDammeEtAl2020,
  author = {Viatte, C. and Wang, T. and Van Damme, M. and Dammers, E. and Meleux, F. and Clarisse, L. and Shephard, M.W. and Whitburn, S. and François Coheur, P. and Cady-Pereira, K.E. and Clerbaux, C.},
  title = {Atmospheric ammonia variability and link with particulate matter formation: A case study over the Paris area},
  journal = {Atmospheric Chemistry and Physics},
  year = {2020},
  volume = {20},
  pages = {577-596},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85078237241&doi=10.5194%2facp-20-577-2020&partnerID=40&md5=71215580b90c99c1059fe6b84e94b4c4},
  doi = {10.5194/acp-20-577-2020}
}
Abstract: Atmospheric carbon monoxide (CO) emissions estimated from inverse modeling analyses exhibit large uncertainties, due, in part, to discrepancies in the tropospheric chemistry in atmospheric models. We attempt to reduce the uncertainties in CO emission estimates by constraining the modeled abundance of ozone (O3), nitrogen dioxide (NO2), nitric acid (HNO3), and formaldehyde (HCHO), which are constituents that play a key role in tropospheric chemistry. Using the GEOS-Chem four-dimensional variational (4D-Var) data assimilation system, we estimate CO emissions by assimilating observations of CO from the Measurement of Pollution In the Troposphere (MOPITT) and the Infrared Atmospheric Sounding Interferometer (IASI), together with observations of O3 from the Optical Spectrograph and InfraRed Imager System (OSIRIS) and IASI, NO2 and HCHO from the Ozone Monitoring Instrument (OMI), and HNO3 from the Microwave Limb Sounder (MLS). Although our focus is on quantifying CO emission estimates, we also infer surface emissions of nitrogen oxides (NOx = NO + NO2) and isoprene. Our results reveal that this multiple species chemical data assimilation produces a chemical consistent state that effectively adjusts the CO–O3–OH coupling in the model. The O3-induced changes in OH are particularly large in the tropics. We show that the analysis results in a tropospheric chemical state that is better constrained. Our experiments also evaluate the inferred CO emission estimates from major anthropogenic, biomass burning and biogenic sources. © Springer Nature Switzerland AG 2020.
BibTeX:
@conference{ZhangJonesKellerEtAl2020,
  author = {Zhang, X. and Jones, D. and Keller, M. and Jiang, Z. and Bourassa, A.E. and Degenstein, D.A. and Clerbaux, C.},
  title = {Global CO Emission Estimates Inferred from Assimilation of MOPITT CO, Together with Observations of O3, NO2, HNO3, and HCHO},
  journal = {Springer Proceedings in Complexity},
  year = {2020},
  pages = {219-224},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076745071&doi=10.1007%2f978-3-030-22055-6_34&partnerID=40&md5=0d90c52df17fd7e62e60f062e5151981},
  doi = {10.1007/978-3-030-22055-6_34}
}
Abstract: It has been suggested that dust storms efficiently transport water vapor from the near-surface to the middle atmosphere on Mars. Knowledge of the water vapor vertical profile during dust storms is important to understand water escape. During Martian Year 34, two dust storms occurred on Mars: a global dust storm (June to mid-September 2018) and a regional storm (January 2019). Here we present water vapor vertical profiles in the periods of the two dust storms (Ls = 162–260° and Ls = 298–345°) from the solar occultation measurements by Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO). We show a significant increase of water vapor abundance in the middle atmosphere (40–100 km) during the global dust storm. The water enhancement rapidly occurs following the onset of the storm (Ls~190°) and has a peak at the most active period (Ls~200°). Water vapor reaches very high altitudes (up to 100 km) with a volume mixing ratio of ~50 ppm. The water vapor abundance in the middle atmosphere shows high values consistently at 60°S-60°N at the growth phase of the dust storm (Ls = 195°–220°), and peaks at latitudes greater than 60°S at the decay phase (Ls = 220°–260°). This is explained by the seasonal change of meridional circulation: from equinoctial Hadley circulation (two cells) to the solstitial one (a single pole-to-pole cell). We also find a conspicuous increase of water vapor density in the middle atmosphere at the period of the regional dust storm (Ls = 322–327°), in particular at latitudes greater than 60°S. ©2019. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{AokiVandaeleDaerdenEtAl2019,
  author = {Aoki, S. and Vandaele, A.C. and Daerden, F. and Villanueva, G.L. and Liuzzi, G. and Thomas, I.R. and Erwin, J.T. and Trompet, L. and Robert, S. and Neary, L. and Viscardy, S. and Clancy, R.T. and Smith, M.D. and Lopez-Valverde, M.A. and Hill, B. and Ristic, B. and Patel, M.R. and Bellucci, G. and Lopez-Moreno, J.-J. and Vandaele, A.C. and López-Moreno, J.-J. and Bellucci, G. and Patel, M.R. and Alonso-Rodrigo, G. and Aoki, S. and Altieri, F. and Bauduin, S. and Bolsée, D. and Carrozzo, G. and Todd Clancy, R. and Cloutis, E. and Crismani, M. and Daerden, F. and Da Pieve, F. and D'Aversa, E. and Depiesse, C. and Erwin, J.T. and Etiope, G. and Fedorova, A.A. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Geminale, A. and Gérard, J.-C. and Giuranna, M. and Gkouvelis, L. and Gonzalez-Galindo, F. and Holmes, J. and Hubert, B. and Ignatiev, N.I. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Kass, D. and Kleinböhl, A. and Lanciano, O. and Lefèvre, F. and Lewis, S. and Liuzzi, G. and López-Puertas, M. and López-Valverde, M. and Mahieux, A. and Mason, J. and Mege, D. and Mumma, M.J. and Nakagawa, H. and Neary, L. and Neefs, E. and Novak, R.E. and Oliva, F. and Piccialli, A. and Renotte, E. and Ritter, B. and Robert, S. and Schmidt, F. and Schneider, N. and Sindoni, G. and Smith, M.D. and Teanby, N.A. and Thiemann, E. and Thomas, I.R. and Trokhimovskiy, A. and Trompet, L. and Auwera, J.V. and Villanueva, G.L. and Viscardy, S. and Whiteway, J. and Wilquet, V. and Willame, Y. and Wolff, M.J. and Wolkenberg, P. and Yelle, R. and del Moral Beatriz, A. and Barzin, P. and Beeckman, B. and BenMoussa, A. and Berkenbosch, S. and Biondi, D. and Bonnewijn, S. and Candini, G.P. and Clairquin, R. and Cubas, J. and Giordanengo, B. and Gissot, S. and Gomez, A. and Hathi, B. and Zafra, J.J. and Leese, M. and Maes, J. and Mazy, E. and Mazzoli, A. and Meseguer, J. and Morales, R. and Orban, A. and Pastor-Morales, M. and Perez-grande, I. and Queirolo, C. and Ristic, R. and Gomez, J.R. and Saggin, B. and Samain, V. and Sanz Andres, A. and Sanz, R. and Simar, J.-F. and Thibert, T. and the NOMAD team},
  title = {Water Vapor Vertical Profiles on Mars in Dust Storms Observed by TGO/NOMAD},
  journal = {Journal of Geophysical Research: Planets},
  year = {2019},
  volume = {124},
  pages = {3482-3497},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077908040&doi=10.1029%2f2019JE006109&partnerID=40&md5=6482664f458609dcb505795b5e2dcbe0},
  doi = {10.1029/2019JE006109}
}
Abstract: Volcanic sulfate aerosols play a key role in air quality and climate. However, the rate of oxidation of sulfur dioxide (SO2) precursor gas to sulfate aerosols (SO2-4 ) in volcanic plumes is poorly known, especially in the troposphere. Here we determine the chemical speciation as well as the intensity and temporal persistence of the impact on air quality of sulfate aerosols from the 2014-2015 Holuhraun flood lava eruption of Icelandic volcano Bárdarbunga. To do so, we jointly analyse a set of SO2 observations from satellite (OMPS and IASI) and ground-level measurements from air quality monitoring stations together with high temporal resolution mass spectrometry measurements of an Aerosol Chemical Speciation Monitor (ACSM) performed far from the volcanic source. We explore month/year long ACSM data in France from stations in contrasting environments, close and far from industrial sulfur-rich activities. We demonstrate that volcanic sulfate aerosols exhibit a distinct chemical signature in urban/rural conditions, with NO3 : SO4 mass concentration ratios lower than for non-volcanic background aerosols. These results are supported by thermodynamic simulations of aerosol composition, using the ISORROPIA II model, which show that ammonium sulfate aerosols are preferentially formed at a high concentration of sulfate, leading to a decrease in the production of particulate ammonium nitrate. Such a chemical signature is however more difficult to identify at heavily polluted industrial sites due to a high level of background noise in sulfur. Nevertheless, aged volcanic sulfates can be distinguished from freshly emitted industrial sulfates according to their contrasting degree of anion neutralization. Combining AERONET (AErosol RObotic NETwork) sunphotometric data with ACSM observations, we also show a long persistence over weeks of pollution in volcanic sulfate aerosols, while SO2 pollution disappears in a few days at most. Finally, gathering 6-month long datasets from 27 sulfur monitoring stations of the EMEP (European Monitoring and Evaluation Programme) network allows us to demonstrate a much broader large-scale European pollution, in both SO2 and SO4, associated with the Holuhraun eruption, from Scandinavia to France. While widespread SO2 anomalies, with ground-level mass concentrations far exceeding background values, almost entirely result from the volcanic source, the origin of sulfate aerosols is more complex. Using a multi-site concentration-weighted trajectory analysis, emissions from the Holuhraun eruption are shown to be one of the main sources of SO4 at all EMEP sites across Europe and can be distinguished from anthropogenic emissions from eastern Europe but also from Great Britain. A wide variability in SO2 : SO4 mass concentration ratios, ranging from 0.8 to 8.0, is shown at several stations geographically dispersed at thousands of kilometres from the eruption site. Despite this apparent spatial complexity, we demonstrate that these mass oxidation ratios can be explained by a simple linear dependency on the age of the plume, with a SO2-to-SO4 oxidation rate of 0.23 h-1. Most current studies generally focus on SO2, an unambiguous and more readily measured marker of the volcanic plume. However, the long persistence of the chemical fingerprint of volcanic sulfate aerosols at continental scale, as shown for the Holuhraun eruption here, casts light on the impact of tropospheric eruptions and passive degassing activities on air quality, health, atmospheric chemistry and climate. © 2019 Author(s).
BibTeX:
@article{BoichuFavezRiffaultEtAl2019,
  author = {Boichu, M. and Favez, O. and Riffault, V. and Petit, J.-E. and Zhang, Y. and Brogniez, C. and Sciare, J. and Chiapello, I. and Clarisse, L. and Zhang, S. and Pujol-Söhne, N. and Tison, E. and Delbarre, H. and Goloub, P.},
  title = {Large-scale particulate air pollution and chemical fingerprint of volcanic sulfate aerosols from the 2014-2015 Holuhraun flood lava eruption of Bárdarbunga volcano (Iceland)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2019},
  volume = {19},
  pages = {14253-14287},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075774667&doi=10.5194%2facp-19-14253-2019&partnerID=40&md5=cb381d9042f251dd76e7b70eb83e42b5},
  doi = {10.5194/acp-19-14253-2019}
}
Abstract: The knowledge of the carbon monoxide (CO) abundance on Mars is essential in order to assess the processes driving the carbon cycle on the planet. Solar occultation measurements provide vertically-resolved measurements of CO from a few kilometers to higher altitudes and can be complemented by nadir measurements to enhance the spatial coverage of observations and the monitoring of the near-surface layer. Up to now, in the shortwave, CO retrievals from nadir observations have, however, mostly been performed on mean spectra and only total column abundances have been obtained. In this work we explore the possibility of exploiting nadir measurements from the Planetary Fourier Spectrometer (PFS) in the 1–0 band of CO (centered at 2143 cm−1) to retrieve vertical profiles of that species on individual measurement. The retrievals are performed for a set of 16 selected PFS spectra with reasonable signal-to-noise ratios by applying the Optimal Estimation Method (OEM) with appropriate constraints, built from model simulations of the Martian atmosphere. The retrieved profiles are characterized in terms of vertical sensitivity and errors. We demonstrate, in particular, that the PFS nadir measurements carry information mostly on the CO column below 15 km, with a maximum sensitivity to the near-surface atmosphere. These measurements allow to substantially reduce the prior uncertainty on the CO abundance in this altitude range, with an estimated total retrieval error on the column-averaged volume mixing ratio (VMR) around 10%. We show that the set of retrieved VMRs are in the range of values reported from other instruments. The retrieved VMRs also capture well the known spatial and seasonal CO variability, which is promising in the perspective of better exploiting the exceptional set of PFS observations on Mars. © 2019 Elsevier Ltd
BibTeX:
@article{BoucheBauduinGiurannaEtAl2019,
  author = {Bouche, J. and Bauduin, S. and Giuranna, M. and Robert, S. and Aoki, S. and Vandaele, A.C. and Erwin, J.T. and Daerden, F. and Wolkenberg, P. and Coheur, P.-F.},
  title = {Retrieval and characterization of carbon monoxide (CO) vertical profiles in the Martian atmosphere from observations of PFS/MEX},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2019},
  volume = {238},
  article number = {106498},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066807504&doi=10.1016%2fj.jqsrt.2019.05.009&partnerID=40&md5=4940f18b127e2a180cc6660dc70313c3},
  doi = {10.1016/j.jqsrt.2019.05.009}
}
Abstract: Aerosol is an important component of the Earth's atmosphere, affecting weather, climate, and diverse elements of the biosphere. Satellite sounders are an essential tool for measuring the highly variable distributions of atmospheric aerosol. Here we present a new algorithm for estimating atmospheric dust optical depths and associated retrieval uncertainties from spectral radiance measurements of the Infrared Atmospheric Sounding Interferometer (IASI). The retrieval is based on the calculation of a dust index and on a neural network trained with synthetic IASI spectra. It has an inherent high sensitivity to dust and efficiently discriminates dust from other aerosols. In particular, over remote dust-free areas, the retrieved levels of optical depth have a low bias. Over sea, noise levels are markedly lower than over land. Performance over deserts is comparable to that of other land surfaces. We use ground-based coarse mode aerosol measurements from the AErosol RObotic NETwork to validate the new product. The overall assessment is favorable, with standard deviations in line with estimated uncertainties, low biases, and high correlation coefficients. However, a systematic relative bias occurs between sites dominated by African and Asian dust sources respectively, likely linked to differences in mineralogy. The retrieval has been performed on over a decade of IASI data, and the resulting data set is now publicly available. We present a global seasonal dust climatology based on this record and compare it with those obtained from independent satellite measurements (Moderate Resolution Imaging Spectroradiometer and a third-party IASI product) and dust optical depth from the ECMWF model. ©2019. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{ClarisseClerbauxFrancoEtAl2019,
  author = {Clarisse, L. and Clerbaux, C. and Franco, B. and Hadji-Lazaro, J. and Whitburn, S. and Kopp, A.K. and Hurtmans, D. and Coheur, P.-F.},
  title = {A Decadal Data Set of Global Atmospheric Dust Retrieved From IASI Satellite Measurements},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2019},
  volume = {124},
  pages = {1618-1647},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85060947485&doi=10.1029%2f2018JD029701&partnerID=40&md5=a2f83793aab5ba0c82c2f44a776356bd},
  doi = {10.1029/2018JD029701}
}
Abstract: As a precursor of atmospheric aerosols, ammonia (NH3) is one of the primary gaseous air pollutants. Given its short atmospheric lifetime, ambient NH3 concentrations are dominated by local sources. In a recent study, Van Damme et al. (2018) have highlighted the importance of NH3 point sources, especially those associated with feedlots and industrial ammonia production. Their emissions were shown to be largely underestimated in bottom-up emission inventories. The discovery was made possible thanks to the use of oversampling techniques applied to 9 years of global daily IASI NH3 satellite measurements. Oversampling allows one to increase the spatial resolution of averaged satellite data beyond what the satellites natively offer. Here we apply for the first time superresolution techniques, which are commonplace in many fields that rely on imaging, to measurements of an atmospheric sounder, whose images consist of just single pixels. We demonstrate the principle on synthetic data and on IASI measurements of a surface parameter. Superresolution is a priori less suitable to be applied on measurements of variable atmospheric constituents, in particular those affected by transport. However, by first applying the wind-rotation technique, which was introduced in the study of other primary pollutants, superresolution becomes highly effective in mapping NH3 at a very high spatial resolution. We show that plume transport can be revealed in greater detail than what was previously thought to be possible. Next, using this wind-adjusted superresolution technique, we introduce a new type of NH3 map that allows tracking down point sources more easily than the regular oversampled average. On a subset of known emitters, the source could be located within a median distance of 1.5 km. We subsequently present a new global point-source catalog consisting of more than 500 localized and categorized point sources. Compared to our previous catalog, the number of identified sources more than doubled. In addition, we refined the classification of industries into five categories - fertilizer, coking, soda ash, geothermal and explosives industries - and introduced a new urban category for isolated NH3 hotspots over cities. The latter mainly consists of African megacities, as clear isolation of such urban hotspots is almost never possible elsewhere due to the presence of a diffuse background with higher concentrations. The techniques presented in this paper can most likely be exploited in the study of point sources of other short-lived atmospheric pollutants such as SO2 and NO2. © 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
BibTeX:
@article{ClarisseVanDammeClerbauxEtAl2019,
  author = {Clarisse, L. and Van Damme, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {Tracking down global NH3 point sources with wind-adjusted superresolution},
  journal = {Atmospheric Measurement Techniques},
  year = {2019},
  volume = {12},
  pages = {5457-5473},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073696326&doi=10.5194%2famt-12-5457-2019&partnerID=40&md5=d04bbd889435cbda9325a6f02062c4db},
  doi = {10.5194/amt-12-5457-2019}
}
Abstract: In a recent global analysis of satellite-derived atmospheric NH 3 data, a hotspot was observed in the vicinity of Lake Natron, Tanzania. The lake is in the centre of an endorheic (limited drainage) basin and has shallow, saline-alkaline waters. Its remote location and the absence of nearby large anthropogenic sources suggest that the observed NH 3 is mainly of natural origin. Here we explore 10 years of IASI NH 3 satellite data and other publicly available datasets over the area to characterize the natural NH 3 emissions in this unique ecosystem. Temporal analysis reveals that the emissions are episodic and linked with the lake’s surface area. The largest NH 3 column loadings generally occur at the end of the dry season in September–November over Lake Natron’s largest mudflat, that is exposed with receding water levels. The timing is different from the agricultural dominated NH 3 emissions in the wider Natron area, which peak early in the year, after the first wet season. The likely source of NH 3 at Lake Natron is decomposition of organic material, either from rivers and springs or produced in the lake (plankton, bird excreta). High temperatures and alkalinity are known to promote NH 3 losses from soda lakes. We formulate six processes that may explain why the largest losses are observed specifically over concentrated brines and/or exposed sediments. As a by-product, we also show that hyperspectral infrared sounders such as IASI are capable of mapping different types of evaporative minerals such as trona and thermonatrite. © 2019, The Author(s).
BibTeX:
@article{ClarisseVanDammeGardnerEtAl2019,
  author = {Clarisse, L. and Van Damme, M. and Gardner, W. and Coheur, P.-F. and Clerbaux, C. and Whitburn, S. and Hadji-Lazaro, J. and Hurtmans, D.},
  title = {Atmospheric ammonia (NH 3 ) emanations from Lake Natron’s saline mudflats},
  journal = {Scientific Reports},
  year = {2019},
  volume = {9},
  article number = {4441},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063006820&doi=10.1038%2fs41598-019-39935-3&partnerID=40&md5=002b8066011ec93c869e8efe98cb1a92},
  doi = {10.1038/s41598-019-39935-3}
}
Abstract: Ammonia (NH3) is an essential reactive nitrogen species in the biosphere and through its use in agriculture in the form of fertilizer (important for sustaining humankind). The current emission levels, however, are up to 4 times higher than in the previous century and continue to grow with uncertain consequences to human health and the environment. While NH3 at its current levels is a hazard to environmental and human health, the atmospheric budget is still highly uncertain, which is a product of an overall lack of measurements. The capability to measure NH3 with satellites has opened up new ways to study the atmospheric NH3 budget. In this study, we present the first estimates of NH3 emissions, lifetimes and plume widths from large (>∼ 5 kt yr-1) agricultural and industrial point sources from Cross-Track Infrared Sounder (CrIS) satellite observations across the globe with a consistent methodology. The same methodology is also applied to the Infrared Atmospheric Sounding Interferometer (IASI) (A and B) satellite observations, and we show that the satellites typically provide comparable results that are within the uncertainty of the estimates. The computed NH3 lifetime for large point sources is on average 2:35±1:16 h. For the 249 sources with emission levels detectable by the CrIS satellite, there are currently 55 locations missing (or underestimated by more than an order of magnitude) from the current Hemispheric Transport Atmospheric Pollution version 2 (HTAPv2) emission inventory and only 72 locations with emissions within a factor of 2 compared to the inventories. The CrIS emission estimates give a total of 5622 kt yr-1, for the sources analyzed in this study, which is around a factor of ∼ 2:5 higher than the emissions reported in HTAPv2. Furthermore, the study shows that it is possible to accurately detect short-and long-Term changes in emissions, demonstrating the possibility of using satellite-observed NH3 to constrain emission inventories. © 2019 Author(s).
BibTeX:
@article{DammersMcLindenGriffinEtAl2019,
  author = {Dammers, E. and McLinden, C.A. and Griffin, D. and Shephard, M.W. and Van Der Graaf, S. and Lutsch, E. and Schaap, M. and Gainairu-Matz, Y. and Fioletov, V. and Van Damme, M. and Whitburn, S. and Clarisse, L. and Cady-Pereira, K. and Clerbaux, C. and Francois Coheur, P. and Erisman, J.-W.},
  title = {NH3 emissions from large point sources derived from CrIS and IASI satellite observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2019},
  volume = {19},
  pages = {12261-12293},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073622984&doi=10.5194%2facp-19-12261-2019&partnerID=40&md5=ba5fe2e2fd2be802d70ac923008eea89},
  doi = {10.5194/acp-19-12261-2019}
}
Abstract: As one of the most abundant oxygenated volatile organic compounds in the atmosphere, acetone (CH3C[O]CH3) influences atmospheric oxidants levels and ozone formation. Here we report the first unambiguous identification of acetone from the nadir-viewing satellite sounder Infrared Atmospheric Sounding Interferometer (IASI). Via a neural network-based retrieval approach that was previously applied to the retrieval of other weak absorbers, we obtain daily global acetone retrievals. A first intercomparison with independent measurements is conducted. As the retrieval method is computationally fast, it allowed the full reprocessing of the 2007–2018 IASI time series. Analysis of the retrieved global product and its seasonality suggests that emissions of acetone and precursors from the terrestrial biosphere at Northern Hemisphere middle and high latitudes are the main contributors to the atmospheric acetone abundance, more than year-round oxidation of anthropogenic isoalkanes. Remarkably, biomass burning does not appear to be a strong global source of acetone. ©2019. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{FrancoClarisseStavrakouEtAl2019,
  author = {Franco, B. and Clarisse, L. and Stavrakou, T. and Müller, J.-F. and Pozzer, A. and Hadji-Lazaro, J. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {Acetone Atmospheric Distribution Retrieved From Space},
  journal = {Geophysical Research Letters},
  year = {2019},
  volume = {46},
  pages = {2884-2893},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062778615&doi=10.1029%2f2019GL082052&partnerID=40&md5=902b4b01129e9520d48721e165fadcf2},
  doi = {10.1029/2019GL082052}
}
Abstract: The accurate determination of the location, height, and loading of sulfur dioxide (SO2) plumes emitted by volcanic eruptions is essential for aviation safety. The SO2 layer height is also one of the most critical parameters with respect to determining the impact on the climate. Retrievals of SO2 plume height have been carried out using satellite UV backscatter measurements, but, until now, such algorithms are very time-consuming. We have developed an extremely fast yet accurate SO2 layer height retrieval using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm. This is the first time the algorithm has been applied to measurements from the TROPOMI instrument onboard the Sentinel-5 Precursor platform. In this paper, we demonstrate the ability of the FP_ILM algorithm to retrieve SO2 plume layer heights in near-real-time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU. We present SO2 layer height results for the volcanic eruptions of Sinabung in February 2018, Sierra Negra in June 2018, and Raikoke in June 2019, observed by TROPOMI. © 2019 BMJ Publishing Group. All rights reserved.
BibTeX:
@article{HedeltEfremenkoLoyolaEtAl2019,
  author = {Hedelt, P. and Efremenko, D.S. and Loyola, D.G. and Spurr, R. and Clarisse, L.},
  title = {Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM},
  journal = {Atmospheric Measurement Techniques},
  year = {2019},
  volume = {12},
  pages = {5503-5517},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073753269&doi=10.5194%2famt-12-5503-2019&partnerID=40&md5=454af9685d1513c41304a090cc43d279},
  doi = {10.5194/amt-12-5503-2019}
}
Abstract: The detection of methane on Mars has been interpreted as indicating that geochemical or biotic activities could persist on Mars today1. A number of different measurements of methane show evidence of transient, locally elevated methane concentrations and seasonal variations in background methane concentrations2–5. These measurements, however, are difficult to reconcile with our current understanding of the chemistry and physics of the Martian atmosphere6,7, which—given methane’s lifetime of several centuries—predicts an even, well mixed distribution of methane1,6,8. Here we report highly sensitive measurements of the atmosphere of Mars in an attempt to detect methane, using the ACS and NOMAD instruments onboard the ESA-Roscosmos ExoMars Trace Gas Orbiter from April to August 2018. We did not detect any methane over a range of latitudes in both hemispheres, obtaining an upper limit for methane of about 0.05 parts per billion by volume, which is 10 to 100 times lower than previously reported positive detections2,4. We suggest that reconciliation between the present findings and the background methane concentrations found in the Gale crater4 would require an unknown process that can rapidly remove or sequester methane from the lower atmosphere before it spreads globally. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX:
@article{KorablevVandaeleMontmessinEtAl2019,
  author = {Korablev, O. and Vandaele, A.C. and Montmessin, F. and Fedorova, A.A. and Trokhimovskiy, A. and Forget, F. and Lefèvre, F. and Daerden, F. and Thomas, I.R. and Trompet, L. and Erwin, J.T. and Aoki, S. and Robert, S. and Neary, L. and Viscardy, S. and Grigoriev, A.V. and Ignatiev, N.I. and Shakun, A. and Patrakeev, A. and Belyaev, D.A. and Bertaux, J.-L. and Olsen, K.S. and Baggio, L. and Alday, J. and Ivanov, Y.S. and Ristic, B. and Mason, J. and Willame, Y. and Depiesse, C. and Hetey, L. and Berkenbosch, S. and Clairquin, R. and Queirolo, C. and Beeckman, B. and Neefs, E. and Patel, M.R. and Bellucci, G. and López-Moreno, J.-J. and Wilson, C.F. and Etiope, G. and Zelenyi, L. and Svedhem, H. and Vago, J.L. and Alonso-Rodrigo, G. and Altieri, F. and Anufreychik, K. and Arnold, G. and Bauduin, S. and Bolsée, D. and Carrozzo, G. and Clancy, R.T. and Cloutis, E. and Crismani, M. and Da Pieve, F. and D’Aversa, E. and Duxbury, N. and Encrenaz, T. and Fouchet, T. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Gérard, J.-C. and Giuranna, M. and Gkouvelis, L. and Gonzalez-Galindo, F. and Grassi, D. and Guerlet, S. and Hartogh, P. and Holmes, J. and Hubert, B. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Kass, D. and Khatuntsev, I. and Kleinböhl, A. and Kokonkov, N. and Krasnopolsky, V. and Kuzmin, R. and Lacombe, G. and Lanciano, O. and Lellouch, E. and Lewis, S. and Luginin, M. and Liuzzi, G. and López-Puertas, M. and López-Valverde, M. and Määttänen, A. and Mahieux, A. and Marcq, E. and Martin-Torres, J. and Maslov, I. and Medvedev, A. and Millour, E. and Moshkin, B. and Mumma, M.J. and Nakagawa, H. and Novak, R.E. and Oliva, F. and Patsaev, D. and Piccialli, A. and Quantin-Nataf, C. and Renotte, E. and Ritter, B. and Rodin, A. and Schmidt, F. and Schneider, N. and Shematovich, V. and Smith, M.D. and Teanby, N.A. and Thiemann, E. and Thomas, N. and Vander Auwera, J. and Vazquez, L. and Villanueva, G. and Vincendon, M. and Whiteway, J. and Wilquet, V. and Wolff, M.J. and Wolkenberg, P. and Yelle, R. and Young, R. and Zasova, L. and Zorzano, M.P. and The ACS and NOMAD Science Teams},
  title = {No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations},
  journal = {Nature},
  year = {2019},
  volume = {568},
  pages = {517-520},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064268492&doi=10.1038%2fs41586-019-1096-4&partnerID=40&md5=2b5f1e2c8100be6284388798d7d3c4b5},
  doi = {10.1038/s41586-019-1096-4}
}
Abstract: The surname of author Cathy Quantin-Nataf was misspelled ‘Quantin-Nata’, authors Ehouarn Millour and Roland Young were missing from the ACS and NOMAD Science Teams list, and minor changes have been made to the author and affiliation lists; see accompanying Amendment. These errors have been corrected online. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX:
@article{KorablevVandaeleMontmessinEtAl2019a,
  author = {Korablev, O. and Vandaele, A.C. and Montmessin, F. and Fedorova, A.A. and Trokhimovskiy, A. and Forget, F. and Lefèvre, F. and Daerden, F. and Thomas, I.R. and Trompet, L. and Erwin, J.T. and Aoki, S. and Robert, S. and Neary, L. and Viscardy, S. and Grigoriev, A.V. and Ignatiev, N.I. and Shakun, A. and Patrakeev, A. and Belyaev, D.A. and Bertaux, J.-L. and Olsen, K.S. and Baggio, L. and Alday, J. and Ivanov, Y.S. and Ristic, B. and Mason, J. and Willame, Y. and Depiesse, C. and Hetey, L. and Berkenbosch, S. and Clairquin, R. and Queirolo, C. and Beeckman, B. and Neefs, E. and Patel, M.R. and Bellucci, G. and López-Moreno, J.-J. and Wilson, C.F. and Etiope, G. and Zelenyi, L. and Svedhem, H. and Vago, J.L. and Alonso-Rodrigo, G. and Altieri, F. and Anufreychik, K. and Arnold, G. and Bauduin, S. and Bolsée, D. and Carrozzo, G. and Clancy, R.T. and Cloutis, E. and Crismani, M. and Da Pieve, F. and D’Aversa, E. and Duxbury, N. and Encrenaz, T. and Fouchet, T. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Gérard, J.-C. and Giuranna, M. and Gkouvelis, L. and Gonzalez-Galindo, F. and Grassi, D. and Guerlet, S. and Hartogh, P. and Holmes, J. and Hubert, B. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Kass, D. and Khatuntsev, I. and Kleinböhl, A. and Kokonkov, N. and Krasnopolsky, V. and Kuzmin, R. and Lacombe, G. and Lanciano, O. and Lellouch, E. and Lewis, S. and Luginin, M. and Liuzzi, G. and López-Puertas, M. and López-Valverde, M. and Määttänen, A. and Mahieux, A. and Marcq, E. and Martin-Torres, J. and Maslov, I. and Medvedev, A. and Millour, E. and Moshkin, B. and Mumma, M.J. and Nakagawa, H. and Novak, R.E. and Oliva, F. and Patsaev, D. and Piccialli, A. and Quantin-Nataf, C. and Renotte, E. and Ritter, B. and Rodin, A. and Schmidt, F. and Schneider, N. and Shematovich, V. and Smith, M.D. and Teanby, N.A. and Thiemann, E. and Thomas, N. and Vander Auwera, J. and Vazquez, L. and Villanueva, G. and Vincendon, M. and Whiteway, J. and Wilquet, V. and Wolff, M.J. and Wolkenberg, P. and Yelle, R. and Young, R. and Zasova, L. and Zorzano, M.P. and The ACS and NOMAD Science Teams},
  title = {Publisher Correction: No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations (Nature, (2019), 568, 7753, (517-520), 10.1038/s41586-019-1096-4)},
  journal = {Nature},
  year = {2019},
  volume = {569},
  pages = {E2},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064678079&doi=10.1038%2fs41586-019-1164-9&partnerID=40&md5=6a062945ee0d1fb60dc135f1b17817e0},
  doi = {10.1038/s41586-019-1164-9}
}
Abstract: Air pollution reaching hazardous levels in many Chinese cities has been a major concern in China over the past decades. New policies have been applied to regulate anthropogenic pollutant emissions, leading to changes in atmospheric composition and in particulate matter (PM) production. Increasing levels of atmospheric ammonia columns have been observed by satellite during recent years. In particular, observations from the Infrared Atmospheric Sounding Interferometer (IASI) reveal an increase of these columns by 15% and 65% from 2011 to 2013 and 2015, respectively, over eastern China. In this paper we performed model simulations for 2011, 2013 and 2015 in order to understand the origin of this increase and to quantify the link between ammonia and the inorganic components of particles: NHC+4(p)/SO2-4(p)/NO-3(p). Interannual change of meteorology can be excluded as a reason: year 2015 meteorology leads to enhanced sulfate production over eastern China, which increases the ammonium and decreases the ammonia content, which is contrary to satellite observations. Reductions in SO2 and NOx emissions from 2011 to 2015 of 37.5% and 21% respectively, as constrained from satellite data, lead to decreased inorganic matter (by 14% for NH+4(p) +SO2-4(p) + NO-3(p)). This in turn leads to increased gaseous NH3(g) tropospheric columns by as much as 24% and 49% (sampled corresponding to IASI data availability) from 2011 to 2013 and 2015 respectively and thus can explain most of the observed increase. © Author(s) 2019.
BibTeX:
@article{LachatreFortems-CheineyForetEtAl2019,
  author = {Lachatre, M. and Fortems-Cheiney, A. and Foret, G. and Siour, G. and Dufour, G. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Van Damme, M. and Beekmann, M.},
  title = {The unintended consequence of SO2 and NO2 regulations over China: Increase of ammonia levels and impact on PM2.5 concentrations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2019},
  volume = {19},
  pages = {6701-6716},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85065977749&doi=10.5194%2facp-19-6701-2019&partnerID=40&md5=9af997a3d5f46c6f00cb48b1aa5dc5fa},
  doi = {10.5194/acp-19-6701-2019}
}
Abstract: The Nadir and Occultation for MArs Discovery instrument (NOMAD), onboard the ExoMars Trace Gas Orbiter (TGO) spacecraft was conceived to observe Mars in solar occultation, nadir, and limb geometries, and will be able to produce an outstanding amount of diverse data, mostly focused on properties of the atmosphere. The infrared channels of the instrument operate by combining an echelle grating spectrometer with an Acousto-Optical Tunable Filter (AOTF). Using in-flight data, we characterized the instrument performance and parameterized its calibration. In particular: an accurate frequency calibration was achieved, together with its variability due to thermal effects on the grating. The AOTF properties and transfer function were also quantified, and we developed and tested a realistic method to compute the spectral continuum transmitted through the coupled grating and AOTF system. The calibration results enabled unprecedented insights into the important problem of the sensitivity of NOMAD to methane abundances in the atmosphere. We also deeply characterized its performance under realistic conditions of varying aerosol abundances, diverse albedos and changing illumination conditions as foreseen over the nominal mission. The results show that, in low aerosol conditions, NOMAD single spectrum, 1σ sensitivity to CH 4 is around 0.33 ppbv at 20 km of altitude when performing solar occultations, and better than 1 ppbv below 30 km. In dusty conditions, we show that the sensitivity drops to 0 below 10 km. In Nadir geometry, results demonstrate that NOMAD will be able to produce seasonal maps of CH 4 with a sensitivity around 5 ppbv over most of planet's surface with spatial integration over 5 × 5° bins. Results show also that such numbers can be improved by a factor of ~10 to ~30 by data binning. Overall, our results quantify NOMAD's capability to address the variable aspects of Martian climate. © 2018 Elsevier Inc.
BibTeX:
@article{LiuzziVillanuevaMummaEtAl2019,
  author = {Liuzzi, G. and Villanueva, G.L. and Mumma, M.J. and Smith, M.D. and Daerden, F. and Ristic, B. and Thomas, I. and Vandaele, A.C. and Patel, M.R. and Lopez-Moreno, J.-J. and Bellucci, G. and Allen, M. and Alonso-Rodrigo, G. and Altieri, F. and Aoki, S. and Bauduin, S. and Bolsée, D. and Clancy, T. and Cloutis, E. and D'Aversa, E. and Depiesse, C. and Erwin, J. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Geminale, A. and Gérard, J.-C. and Gillotay, D. and Giuranna, M. and Gonzalez-Galindo, F. and Hewson, W. and Homes, J. and Ignatiev, N. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Lanciano, O. and Lefèvre, F. and Lewis, S. and López- Puertas, M. and López-Valverde, M. and Mahieux, A. and Mason, J. and Mc Connell, J. and Hiromu Neary Nakagawa, L. and Neefs, E. and Novak, R. and Oliva, F. and Piccialli, A. and Renotte, E. and Robert, S. and Sindoni, G. and Stiepen, A. and Trokhimovskiy, A. and Vander Auwera, J. and Viscardy, S. and Whiteway, J. and Willame, Y. and Wilquet, V. and Wolff, M. and Wolkenberg, P. and Alonso-Rodrigo, G. and Aparicio del Moral, B. and Barzin, P. and Beeckman, B. and BenMoussa, A. and Berkenbosch, S. and Biondi, D. and Bonnewijn, S. and Candini, G.P. and Clairquin, R. and Cubas, J. and Giordanengo, B. and Gissot, S. and Gomez, A. and Hathi, B. and Jeronimo Zafra, J. and Leese, M. and Maes, J. and Mazy, E. and Mazzoli, A. and Meseguer, J. and Morales, R. and Orban, A. and Pastor-Morales, M. and Perez-grande, I. and Queirolo, C. and Rodriguez Gomez, J. and Saggin, B. and Samain, V. and Sanz Andres, A. and Sanz, R. and Simar, J.-F. and Thibert, Tanguy.},
  title = {Methane on Mars: New insights into the sensitivity of CH 4 with the NOMAD/ExoMars spectrometer through its first in-flight calibration},
  journal = {Icarus},
  year = {2019},
  volume = {321},
  pages = {671-690},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058999002&doi=10.1016%2fj.icarus.2018.09.021&partnerID=40&md5=f9b793390d46789a777c68a22527de01},
  doi = {10.1016/j.icarus.2018.09.021}
}
Abstract: From 17–22 August 2017 simultaneous enhancements of ammonia (NH3), carbon monoxide (CO), hydrogen cyanide (HCN), and ethane (C2H6) were detected from ground-based solar absorption Fourier transform infrared (FTIR) spectroscopic measurements at two high-Arctic sites: Eureka (80.05°N, 86.42°W) Nunavut, Canada, and Thule (76.53°N, 68.74°W), Greenland. These enhancements were attributed to wildfires in British Columbia and the Northwest Territories of Canada using FLEXPART back-trajectories and fire locations from Moderate Resolution Imaging Spectroradiometer (MODIS) and found to be the greatest observed enhancements in more than a decade of measurements at Eureka (2006–2017) and Thule (1999–2017). Observations of gas-phase NH3 from these wildfires illustrate that boreal wildfires may be a considerable episodic source of NH3 in the summertime high Arctic. Comparisons of GEOS-Chem model simulations using the Global Fire Assimilation System (GFASv1.2) biomass burning emissions to FTIR measurements and Infrared Atmospheric Sounding Interferometer (IASI) measurements showed that the transport of wildfire emissions to the Arctic was underestimated in GEOS-Chem. However, GEOS-Chem simulations showed that these wildfires contributed to surface layer NH3 and NH4 + enhancements of 0.01–0.11 ppbv and 0.05–1.07 ppbv, respectively, over the Canadian Archipelago from 15–23 August 2017. ©2019. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{LutschStrongJonesEtAl2019,
  author = {Lutsch, E. and Strong, K. and Jones, D.B.A. and Ortega, I. and Hannigan, J.W. and Dammers, E. and Shephard, M.W. and Morris, E. and Murphy, K. and Evans, M.J. and Parrington, M. and Whitburn, S. and Van Damme, M. and Clarisse, L. and Coheur, P.-F. and Clerbaux, C. and Croft, B. and Martin, R.V. and Pierce, J.R. and Fisher, J.A.},
  title = {Unprecedented Atmospheric Ammonia Concentrations Detected in the High Arctic From the 2017 Canadian Wildfires},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2019},
  volume = {124},
  pages = {8178-8202},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85069914379&doi=10.1029%2f2019JD030419&partnerID=40&md5=7927970bc3b1bae0c3170466ee21e452},
  doi = {10.1029/2019JD030419}
}
Abstract: On 3 June 2018 Volcán de Fuego (Guatemala) erupted explosively with unusual intensity, producing wide-spread ash dispersal and pyroclastic flows of >11 km length, which destroyed a community on Fuego's flanks, causing hundreds of fatalities. Here, we analyze satellite measurements of the SO 2 plume emitted during the most intense eruptive phase. Key eruption parameters including the injection height and SO 2 flux time-series indicate a degassing intensity at least three orders of magnitude above baseline levels. Our results suggest a steady ~2.5 hour climactic paroxysmal phase of the eruption with a mass eruption rate of ~1.4kg s −1 based on the combination of plume height estimates and an eruption column model, producing 0.03 ± 0.004 km 3 of tephra. We detect at least 130 kt of emitted SO 2 from satellite images, producing a minimum dissolved magmatic sulfur concentration of 500 ppm. Possible source mechanisms are discussed, which may be useful in assessing the risks posed by future large-magnitude eruptions to the large populations that live on Fuego's flanks. This study shows that even under challenging conditions of a tropical atmosphere during the rainy season, vital eruption parameters to constrain source mechanisms of eruptions can be retrieved from satellite remote sensing data. © 2019 The Authors
BibTeX:
@article{PardiniQueisserNaismithEtAl2019,
  author = {Pardini, F. and Queißer, M. and Naismith, A. and Watson, I.M. and Clarisse, L. and Burton, M.R.},
  title = {Initial constraints on triggering mechanisms of the eruption of Fuego volcano (Guatemala) from 3 June 2018 using IASI satellite data},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2019},
  volume = {376},
  pages = {54-61},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85060223146&doi=10.1016%2fj.jvolgeores.2019.03.014&partnerID=40&md5=e73098965977cae62012d3cd4b6f9d4b},
  doi = {10.1016/j.jvolgeores.2019.03.014}
}
Abstract: Emissions of C 2 -C 5 alkanes from the U.S. oil and gas sector have changed rapidly over the last decade. We use a nested GEOS-Chem simulation driven by updated 2011NEI emissions with aircraft, surface, and column observations to (1) examine spatial patterns in the emissions and observed atmospheric abundances of C 2 -C 5 alkanes over the United States and (2) estimate the contribution of emissions from the U.S. oil and gas industry to these patterns. The oil and gas sector in the updated 2011NEI contributes over 80% of the total U.S. emissions of ethane (C 2 H 6 ) and propane (C 3 H 8 ), and emissions of these species are largest in the central United States. Observed mixing ratios of C 2 -C 5 alkanes show enhancements over the central United States below 2 km. A nested GEOS-Chem simulation underpredicts observed C 3 H 8 mixing ratios in the boundary layer over several U.S. regions, and the relative underprediction is not consistent, suggesting C 3 H 8 emissions should receive more attention moving forward. Our decision to consider only C 4 -C 5 alkane emissions as a single lumped species produces a geographic distribution similar to observations. Due to the increasing importance of oil and gas emissions in the United States, we recommend continued support of existing long-term measurements of C 2 -C 5 alkanes. We suggest additional monitoring of C 2 -C 5 alkanes downwind of northeastern Colorado, Wyoming, and western North Dakota to capture changes in these regions. The atmospheric chemistry modeling community should also evaluate whether chemical mechanisms that lump larger alkanes are sufficient to understand air quality issues in regions with large emissions of these species. ©2018. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Tzompa-SosaHendersonKellerEtAl2019,
  author = {Tzompa-Sosa, Z.A. and Henderson, B.H. and Keller, C.A. and Travis, K. and Mahieu, E. and Franco, B. and Estes, M. and Helmig, D. and Fried, A. and Richter, D. and Weibring, P. and Walega, J. and Blake, D.R. and Hannigan, J.W. and Ortega, I. and Conway, S. and Strong, K. and Fischer, E.V.},
  title = {Atmospheric Implications of Large C 2 -C 5 Alkane Emissions From the U.S. Oil and Gas Industry},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2019},
  volume = {124},
  pages = {1148-1169},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85060624687&doi=10.1029%2f2018JD028955&partnerID=40&md5=417e777542e1a803791c2c23b3ad8601},
  doi = {10.1029/2018JD028955}
}
Abstract: Global dust storms on Mars are rare1,2 but can affect the Martian atmosphere for several months. They can cause changes in atmospheric dynamics and inflation of the atmosphere3, primarily owing to solar heating of the dust3. In turn, changes in atmospheric dynamics can affect the distribution of atmospheric water vapour, with potential implications for the atmospheric photochemistry and climate on Mars4. Recent observations of the water vapour abundance in the Martian atmosphere during dust storm conditions revealed a high-altitude increase in atmospheric water vapour that was more pronounced at high northern latitudes5,6, as well as a decrease in the water column at low latitudes7,8. Here we present concurrent, high-resolution measurements of dust, water and semiheavy water (HDO) at the onset of a global dust storm, obtained by the NOMAD and ACS instruments onboard the ExoMars Trace Gas Orbiter. We report the vertical distribution of the HDO/H2O ratio (D/H) from the planetary boundary layer up to an altitude of 80 kilometres. Our findings suggest that before the onset of the dust storm, HDO abundances were reduced to levels below detectability at altitudes above 40 kilometres. This decrease in HDO coincided with the presence of water-ice clouds. During the storm, an increase in the abundance of H2O and HDO was observed at altitudes between 40 and 80 kilometres. We propose that these increased abundances may be the result of warmer temperatures during the dust storm causing stronger atmospheric circulation and preventing ice cloud formation, which may confine water vapour to lower altitudes through gravitational fall and subsequent sublimation of ice crystals3. The observed changes in H2O and HDO abundance occurred within a few days during the development of the dust storm, suggesting a fast impact of dust storms on the Martian atmosphere. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX:
@article{VandaeleKorablevDaerdenEtAl2019,
  author = {Vandaele, A.C. and Korablev, O. and Daerden, F. and Aoki, S. and Thomas, I.R. and Altieri, F. and López-Valverde, M. and Villanueva, G. and Liuzzi, G. and Smith, M.D. and Erwin, J.T. and Trompet, L. and Fedorova, A.A. and Montmessin, F. and Trokhimovskiy, A. and Belyaev, D.A. and Ignatiev, N.I. and Luginin, M. and Olsen, K.S. and Baggio, L. and Alday, J. and Bertaux, J.-L. and Betsis, D. and Bolsée, D. and Clancy, R.T. and Cloutis, E. and Depiesse, C. and Funke, B. and Garcia-Comas, M. and Gérard, J.-C. and Giuranna, M. and Gonzalez-Galindo, F. and Grigoriev, A.V. and Ivanov, Y.S. and Kaminski, J. and Karatekin, O. and Lefèvre, F. and Lewis, S. and López-Puertas, M. and Mahieux, A. and Maslov, I. and Mason, J. and Mumma, M.J. and Neary, L. and Neefs, E. and Patrakeev, A. and Patsaev, D. and Ristic, B. and Robert, S. and Schmidt, F. and Shakun, A. and Teanby, N.A. and Viscardy, S. and Willame, Y. and Whiteway, J. and Wilquet, V. and Wolff, M.J. and Bellucci, G. and Patel, M.R. and López-Moreno, J.-J. and Forget, F. and Wilson, C.F. and Svedhem, H. and Vago, J.L. and Rodionov, D. and Alonso-Rodrigo, G. and Bauduin, S. and Carrozzo, G. and Crismani, M. and Da Pieve, F. and D’Aversa, E. and Etiope, G. and Fussen, D. and Geminale, A. and Gkouvelis, L. and Holmes, J. and Hubert, B. and Kasaba, Y. and Kass, D. and Kleinböhl, A. and Lanciano, O. and Nakagawa, H. and Novak, R.E. and Oliva, F. and Piccialli, A. and Renotte, E. and Ritter, B. and Schneider, N. and Sindoni, G. and Thiemann, E. and Vander Auwera, J. and Wolkenberg, P. and Yelle, R. and Anufreychik, K. and Arnold, G. and Bertaux, J.-L. and Duxbury, N. and Fouchet, T. and Grassi, D. and Guerlet, S. and Hartogh, P. and Khatuntsev, I. and Kokonkov, N. and Krasnopolsky, V. and Kuzmin, R. and Lacombe, G. and Lellouch, E. and Määttänen, A. and Marcq, E. and Martin-Torres, J. and Medvedev, A. and Millour, E. and Moshkin, B. and Patel, M.R. and Quantin-Nataf, C. and Rodin, A. and Shematovich, V. and Thomas, N. and Trokhimovsky, A. and Vazquez, L. and Vincendon, M. and Young, R. and Zasova, L. and Zelenyi, L. and Zorzano, M.P. and NOMAD Science Team and ACS Science Team},
  title = {Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter},
  journal = {Nature},
  year = {2019},
  volume = {568},
  pages = {521-525},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064267043&doi=10.1038%2fs41586-019-1097-3&partnerID=40&md5=7ad806e3c87ce2497a84089b2db86e54},
  doi = {10.1038/s41586-019-1097-3}
}
Abstract: The surname of author Cathy Quantin-Nataf was misspelled ‘Quantin-Nata’ , authors Ehouarn Millour and Roland Young were missing from the ACS Science Team list, and minor changes have been made to the author and affiliation lists; see accompanying Amendment. These errors have been corrected online. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX:
@article{VandaeleKorablevDaerdenEtAl2019a,
  author = {Vandaele, A.C. and Korablev, O. and Daerden, F. and Aoki, S. and Thomas, I.R. and Altieri, F. and López-Valverde, M. and Villanueva, G. and Liuzzi, G. and Smith, M.D. and Erwin, J.T. and Trompet, L. and Fedorova, A.A. and Montmessin, F. and Trokhimovskiy, A. and Belyaev, D.A. and Ignatiev, N.I. and Luginin, M. and Olsen, K.S. and Baggio, L. and Alday, J. and Bertaux, J.-L. and Betsis, D. and Bolsée, D. and Clancy, R.T. and Cloutis, E. and Depiesse, C. and Funke, B. and Garcia-Comas, M. and Gérard, J.-C. and Giuranna, M. and Gonzalez-Galindo, F. and Grigoriev, A.V. and Ivanov, Y.S. and Kaminski, J. and Karatekin, O. and Lefèvre, F. and Lewis, S. and López-Puertas, M. and Mahieux, A. and Maslov, I. and Mason, J. and Mumma, M.J. and Neary, L. and Neefs, E. and Patrakeev, A. and Patsaev, D. and Ristic, B. and Robert, S. and Schmidt, F. and Shakun, A. and Teanby, N.A. and Viscardy, S. and Willame, Y. and Whiteway, J. and Wilquet, V. and Wolff, M.J. and Bellucci, G. and Patel, M.R. and López-Moreno, J.-J. and Forget, F. and Wilson, C.F. and Young, R. and Svedhem, H. and Vago, J.L. and Rodionov, D. and Alonso-Rodrigo, G. and Bauduin, S. and Carrozzo, G. and Crismani, M. and Da Pieve, F. and D’Aversa, E. and Etiope, G. and Fussen, D. and Geminale, A. and Gkouvelis, L. and Holmes, J. and Hubert, B. and Kasaba, Y. and Kass, D. and Kleinböhl, A. and Lanciano, O. and Nakagawa, H. and Novak, R.E. and Oliva, F. and Piccialli, A. and Renotte, E. and Ritter, B. and Schneider, N. and Sindoni, G. and Thiemann, E. and Vander Auwera, J. and Wolkenberg, P. and Yelle, R. and Anufreychik, K. and Arnold, G. and Duxbury, N. and Fouchet, T. and Grassi, D. and Guerlet, S. and Hartogh, P. and Khatuntsev, I. and Kokonkov, N. and Krasnopolsky, V. and Kuzmin, R. and Lacombe, G. and Lellouch, E. and Määttänen, A. and Marcq, E. and Martin-Torres, J. and Medvedev, A. and Millour, E. and Moshkin, B. and Quantin-Nataf, C. and Rodin, A. and Shematovich, V. and Thomas, N. and Trokhimovsky, A. and Vazquez, L. and Vincendon, M. and Zasova, L. and Zelenyi, L. and Zorzano, M.P. and ACS Science Team},
  title = {Publisher Correction: Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter (Nature, (2019), 568, 7753, (521-525), 10.1038/s41586-019-1097-3)},
  journal = {Nature},
  year = {2019},
  volume = {569},
  pages = {E1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064696282&doi=10.1038%2fs41586-019-1163-x&partnerID=40&md5=cc329f1c5452a2dd50224ac687fc6319},
  doi = {10.1038/s41586-019-1163-x}
}
Abstract: Accurate measurement of atmospheric particulate matter (PM) absorption coefficient is highly required for study of earth climate change and for monitoring of air quality. In addition, multi-wavelength measurements of PM absorption can provide information on the PM chemical composition (black carbon or brown carbon). A multi-wavelengths photoacoustic (MW-PA) spectrophone operating at 444, 532 and 660 nm was developed and deployed for filter-free characterization of wavelength-dependent optical properties of PM mass absorption coefficient (MAC) and absorptionÅngström coefficient (AAC). It is worth noting that to date no any AAC of volcanic ashes determined by filter-free measurement have been reported. The developed MW-PA spectrophone was deployed to an intensive field campaign measurement of environmental PM in Grenoble (France). Side-by-side inter-comparison measurements of ambient PM showed a good correlation between the developed MW-PA spectrophone and a reference instrument aethalometer (Magee scientific, AE33). © 2019, Electromagnetics Academy. All rights reserved.
BibTeX:
@article{WangKulinskiHubertEtAl2019,
  author = {Wang, G. and Kulinski, P. and Hubert, P. and Deguine, A. and Petitprez, D. and Crumeyrolle, S. and Fertein, E. and Deboudt, K. and Flament, P. and Sigrist, M.W. and Yi, H. and Chen, W.},
  title = {Filter-free light absorption measurement of volcanic ashes and ambient particulate matter using multi-wavelength photoacoustic spectroscopy},
  journal = {Progress in Electromagnetics Research},
  year = {2019},
  volume = {166},
  pages = {59-74},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074666702&partnerID=40&md5=f83617643e2c0e80bdb26c878e3515a1}
}
Abstract: In this paper, we present the global fingerprint of recent changes in middle-upper stratosphere (MUSt; 25 hPa) ozone (O3) in comparison with lower stratosphere (LSt; 150-25 hPa) O3 derived from the first 10 years of the IASI/Metop-A satellite measurements (January 2008-December 2017). The IASI instrument provides vertically resolved O3 profiles with very high spatial and temporal (twice daily) samplings, allowing O3 changes to be monitored in these two regions of the stratosphere. By applying multivariate regression models with adapted geophysical proxies on daily mean O3 time series, we discriminate anthropogenic trends from various modes of natural variability, such as the El Niño-Southern Oscillation (ENSO). The representativeness of the O3 response to its natural drivers is first examined. One important finding relies on a pronounced contrast between a positive LSt O3 response to ENSO in the extratropics and a negative one in the tropics, with a delay of 3 months, which supports a stratospheric pathway for the ENSO influence on lower stratospheric and tropospheric O3. In terms of trends, we find an unequivocal O3 recovery from the available period of measurements in winter-spring at middle to high latitudes for the two stratospheric layers sounded by IASI ( 35 N-S in the MUSt and 45 S in the LSt) as well as in the total columns at southern latitudes (45 S) where the increase reaches its maximum. These results confirm the effectiveness of the Montreal Protocol and its amendments and represent the first detection of a significant recovery of O3 concurrently in the lower, in the middle-upper stratosphere and in the total column from one single satellite dataset. A significant decline in O3 at northern mid-latitudes in the LSt is also detected, especially in winter-spring of the Northern Hemisphere. Given counteracting trends in the LSt and MUSt at these latitudes, the decline is not categorical in total O3. When freezing the regression coefficients determined for each natural driver over the whole IASI period but adjusting a trend, we calculate a significant speeding up in the O3 response to the decline of O3-depleting substances (ODSs) in the total column, in the LSt and, to a lesser extent, in the MUSt, at high southern latitudes over the year. Results also show a small significant acceleration of the O3 decline at northern mid-latitudes in the LSt and in the total column over the last few years. That, specifically, needs urgent investigation to identify its exact origin and apprehend its impact on climate change. Additional years of IASI measurements would, however, be required to confirm the O3 change rates observed in the stratospheric layers over the last few years. © Author(s) 2019.
BibTeX:
@article{WespesHurtmansChabrillatEtAl2019,
  author = {Wespes, C. and Hurtmans, D. and Chabrillat, S. and Ronsmans, G. and Clerbaux, C. and Coheur, P.-F.},
  title = {Is the recovery of stratospheric O3 speeding up in the Southern Hemisphere? An evaluation from the first IASI decadal record (2008-2017)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2019},
  volume = {19},
  pages = {14031-14056},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075614223&doi=10.5194%2facp-19-14031-2019&partnerID=40&md5=81f55d6445244ec17afc8a44008aa3e7},
  doi = {10.5194/acp-19-14031-2019}
}
Abstract: Since its first measurement 20 years ago by the Infrared Space Observatory (ISO), the water (H2O) mole fraction in Titan's stratosphere remains uncertain due to large differences between the determinations from available measurements. More particularly, the recent measurements made from the Herschel observatory (PACS and HIFI) estimated the H2O mole fraction to be 0.023 ppb at 12.1 mbar. A mixing ratio of 0.14 ppb at 10.7 mbar was, however, retrieved from nadir spatially-resolved observations of Cassini/CIRS. At the same pressure level (10.7 mbar), this makes a difference of a factor of 5.5 between PACS and CIRS measurements, and this has notably prevented current models from fully constraining the oxygen flux flowing into Titan's atmosphere. In this work, we try to understand the differences between the H2O mole fractions estimated from Herschel/PACS and Cassini/CIRS observations. The strategy for this is to 1) analyse recent disc-averaged observations of CIRS to investigate if the observation geometry could explain the previous observed differences, and 2) (re)analyse the three types of observation with the same retrieval scheme to assess if previous differences in retrieval codes/methodology could be responsible for the previous discrepancies. With this analysis, we show that using the same retrieval method better reconcile the previous measurements of these instruments. However, the addition of the disc-averaged CIRS observations, instead of confirming the consistency between the different datasets, reveals discrepancies between one of the CIRS disc-averaged set of observations and PACS measurements. This raises new questions regarding the possibility of latitudinal variations of H2O, which could be triggered by seasonal changes of the meridional circulation. As it has already been shown for nitriles and hydrocarbons, this circulation could potentially impact the latitudinal distribution of H2O through the subsidence or upwelling of air rich in H2O. The possible influence of spatial/time variations of the OH/H2O input flux in Titan's atmosphere is also discussed. The analysis of more observations will be needed in future work to address the questions arising from this work and to improve the understanding of the sources of H2O in Titan's atmosphere. © 2018 Elsevier Inc.
BibTeX:
@article{BauduinIrwinLellouchEtAl2018,
  author = {Bauduin, S. and Irwin, P.G.J. and Lellouch, E. and Cottini, V. and Moreno, R. and Nixon, C.A. and Teanby, N.A. and Ansty, T. and Flasar, F.M.},
  title = {Retrieval of H2O abundance in Titan's stratosphere: A (re)analysis of CIRS/Cassini and PACS/Herschel observations},
  journal = {Icarus},
  year = {2018},
  volume = {311},
  pages = {288-305},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046085804&doi=10.1016%2fj.icarus.2018.04.003&partnerID=40&md5=13f84b66064b776cfe87b31eef7d76e2},
  doi = {10.1016/j.icarus.2018.04.003}
}
BibTeX:
@article{BoudonSearsCoheur2018,
  author = {Boudon, V. and Sears, T. and Coheur, P.-F.},
  title = {Introduction to the special issue on molecular spectroscopy, atmospheric composition and climate change},
  journal = {Journal of Molecular Spectroscopy},
  year = {2018},
  volume = {348},
  pages = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045581329&doi=10.1016%2fj.jms.2018.04.005&partnerID=40&md5=89986c2b7edb0705f5f35d3daa238f5c},
  doi = {10.1016/j.jms.2018.04.005}
}
Abstract:

This paper assesses the quality of IASI (Infrared Atmospheric Sounding Interferometer)/Metop-A (IASI-A) and IASI/Metop-B (IASI-B) ozone (O3) products (total and partial O3 columns) retrieved with the Fast Optimal Retrievals on Layers for IASI Ozone (FORLI-O3; v20151001) software for 9 years (2008-July 2017) through an extensive intercomparison and validation exercise using independent observations (satellite, ground-based and ozonesonde). Compared with the previous version of FORLI-O3 (v20140922), several improvements have been introduced in FORLI-O3 v20151001, including absorbance look-up tables recalculated to cover a larger spectral range, with additional numerical corrections. This leads to a change of ĝ1/4 4 % in the total ozone column (TOC) product, which is mainly associated with a decrease in the retrieved O3 concentration in the middle stratosphere (above 30 hPa/25 km). IASI-A and IASI-B TOCs are consistent, with a global mean difference of less than 0.3 % for both daytime and nighttime measurements; IASI-A is slightly higher than IASI-B. A global difference of less than 2.4 % is found for the tropospheric (TROPO) O3 column product (IASI-A is lower than IASI-B), which is partly due to a temporary issue related to the IASI-A viewing angle in 2015. Our validation shows that IASI-A and IASI-B TOCs are consistent with GOME-2 (Global Ozone Monitoring Experiment-2), Dobson, Brewer, SAOZ (Système d'Analyse par Observation Zénithale) and FTIR (Fourier transform infrared) TOCs, with global mean differences in the range of 0.1 %-2 % depending on the instruments compared. The worst agreement with UV-vis retrieved TOC (satellite and ground) is found at the southern high latitudes. The IASI-A and ground-based TOC comparison for the period from 2008 to July 2017 shows the long-Term stability of IASI-A, with insignificant or small negative drifts of 1 %-3 % decadeĝ'1. The comparison results of IASI-A and IASI-B against smoothed FTIR and ozonesonde partial O3 columns vary with altitude and latitude, with the maximum standard deviation being seen for the 300-150 hPa column (20 %-40 %) due to strong ozone variability and large total retrievals errors. Compared with ozonesonde data, the IASI-A and IASI-B O3 TROPO column (defined as the column between the surface and 300 hPa) is positively biased in the high latitudes (4 %-5 %) and negatively biased in the midlatitudes and tropics (11 %-13 % and 16 %-19 %, respectively). The IASI-A-To-ozonesonde TROPO comparison for the period from 2008 to 2016 shows a significant negative drift in the Northern Hemisphere of ĝ'8.6±3.4 % decadeĝ'1, which is also found in the IASI-A-To-FTIR TROPO comparison. When considering the period from 2011 to 2016, the drift value for the TROPO column decreases and becomes statistically insignificant. The observed negative drifts of the IASI-A TROPO O3 product (8 %-16 % decadeĝ'1) over the 2008-2017 period might be taken into consideration when deriving trends from this product and this time period.

. © Author(s) 2018.
BibTeX:
@article{BoynardHurtmansGaraneEtAl2018,
  author = {Boynard, A. and Hurtmans, D. and Garane, K. and Goutail, F. and Hadji-Lazaro, J. and Elissavet Koukouli, M. and Wespes, C. and Vigouroux, C. and Keppens, A. and Pazmino, A. and Balis, D. and Loyola, D. and Valks, P. and Sussmann, R. and Smale, D. and Coheur, P.-F. and Clerbaux, C.},
  title = {Validation of the IASI FORLI/EUMETSAT ozone products using satellite (GOME-2), ground-based (Brewer-Dobson, SAOZ, FTIR) and ozonesonde measurements},
  journal = {Atmospheric Measurement Techniques},
  year = {2018},
  volume = {11},
  pages = {5125-5152},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053275020&doi=10.5194%2famt-11-5125-2018&partnerID=40&md5=180a833e511b711b4df602f4834dcfda},
  doi = {10.5194/amt-11-5125-2018}
}
Abstract: This paper presents decadal simulations of stratospheric and tropospheric aerosol and its radiative effects by the chemistry general circulation model EMAC constrained with satellite observations in the framework of the ESA Aerosol CCI project such as GOMOS (Global Ozone Monitoring by Occultation of Stars) and (A)ATSR ((Advanced) Along Track Scanning Radiometer) on the ENVISAT (European Environmental Satellite), IASI (Infrared Atmospheric Sounding Interferometer) on MetOp (Meteorological Operational Satellite), and, additionally, OSIRIS (Optical Spectrograph and InfraRed Imaging System). In contrast to most other studies, the extinctions and optical depths from the model are compared to the observations at the original wavelengths of the satellite instruments covering the range from the UV (ultraviolet) to terrestrial IR (infrared). This avoids conversion artifacts and provides additional constraints for model aerosol and interpretation of the observations. MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) SO2 limb measurements are used to identify plumes of more than 200 volcanic eruptions. These three-dimensional SO2 plumes are added to the model SO2 at the eruption times. The interannual variability in aerosol extinction in the lower stratosphere, and of stratospheric aerosol radiative forcing at the tropopause, is dominated by the volcanoes. To explain the seasonal cycle of the GOMOS and OSIRIS observations, desert dust simulated by a new approach and transported to the lowermost stratosphere by the Asian summer monsoon and tropical convection turns out to be essential. This also applies to the radiative heating by aerosol in the lowermost stratosphere. The existence of wet dust aerosol in the lowermost stratosphere is indicated by the patterns of the wavelength dependence of extinction in observations and simulations. Additional comparison with (A)ATSR total aerosol optical depth at different wavelengths and IASI dust optical depth demonstrates that the model is able to represent stratospheric as well as tropospheric aerosol consistently. © Author(s) 2018.
BibTeX:
@article{BruehlSchallockKlingmuellerEtAl2018,
  author = {Brühl, C. and Schallock, J. and Klingmüller, K. and Robert, C. and Bingen, C. and Clarisse, L. and Heckel, A. and North, P. and Rieger, L.},
  title = {Stratospheric aerosol radiative forcing simulated by the chemistry climate model EMAC using Aerosol CCI satellite data},
  journal = {Atmospheric Chemistry and Physics},
  year = {2018},
  volume = {18},
  pages = {12845-12857},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053031554&doi=10.5194%2facp-18-12845-2018&partnerID=40&md5=bf9ec03cdcd9505612c2bc272475c75b},
  doi = {10.5194/acp-18-12845-2018}
}
Abstract: The Tropospheric Ozone Assessment Report (TOAR) is an activity of the International Global Atmospheric Chemistry Project. This paper is a component of the report, focusing on the present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation. Utilizing the TOAR surface ozone database, several figures present the global distribution and trends of daytime average ozone at 2702 non-urban monitoring sites, highlighting the regions and seasons of the world with the greatest ozone levels. Similarly, ozonesonde and commercial aircraft observations reveal ozone's distribution throughout the depth of the free troposphere. Long-term surface observations are limited in their global spatial coverage, but data from remote locations indicate that ozone in the 21st century is greater than during the 1970s and 1980s. While some remote sites and many sites in the heavily polluted regions of East Asia show ozone increases since 2000, many others show decreases and there is no clear global pattern for surface ozone changes since 2000. Two new satellite products provide detailed views of ozone in the lower troposphere across East Asia and Europe, revealing the full spatial extent of the spring and summer ozone enhancements across eastern China that cannot be assessed from limited surface observations. Sufficient data are now available (ozonesondes, satellite, aircraft) across the tropics from South America eastwards to the western Pacific Ocean, to indicate a likely tropospheric column ozone increase since the 1990s. The 2014-2016 mean tropospheric ozone burden (TOB) between 60°N-60°S from five satellite products is 300 Tg ± 4%. While this agreement is excellent, the products differ in their quantification of TOB trends and further work is required to reconcile the differences. Satellites can now estimate ozone's global long-wave radiative effect, but evaluation is difficult due to limited in situ observations where the radiative effect is greatest. © 2018 The Author(s).
BibTeX:
@article{GaudelCooperAncelletEtAl2018,
  author = {Gaudel, A. and Cooper, O.R. and Ancellet, G. and Barret, B. and Boynard, A. and Burrows, J.P. and Clerbaux, C. and Coheur, P.-F. and Cuesta, J. and Cuevas, E. and Doniki, S. and Dufour, G. and Ebojie, F. and Foret, G. and Garcia, O. and Granados-Muñoz, M.J. and Hannigan, J.W. and Hase, F. and Hassler, B. and Huang, G. and Hurtmans, D. and Jaffe, D. and Jones, N. and Kalabokas, P. and Kerridge, B. and Kulawik, S. and Latter, B. and Leblanc, T. and Le Flochmoën, E. and Lin, W. and Liu, J. and Liu, X. and Mahieu, E. and McClure-Begley, A. and Neu, J.L. and Osman, M. and Palm, M. and Petetin, H. and Petropavlovskikh, I. and Querel, R. and Rahpoe, N. and Rozanov, A. and Schultz, M.G. and Schwab, J. and Siddans, R. and Smale, D. and Steinbacher, M. and Tanimoto, H. and Tarasick, D.W. and Thouret, V. and Thompson, A.M. and Trickl, T. and Weatherhead, E. and Wespes, C. and Worden, H.M. and Vigouroux, C. and Xu, X. and Zeng, G. and Ziemke, J.},
  title = {Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation},
  journal = {Elementa},
  year = {2018},
  volume = {6},
  article number = {39},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053711818&doi=10.1525%2felementa.291&partnerID=40&md5=d40f48930ff5607ea7a43c9a3a05bd9c},
  doi = {10.1525/elementa.291}
}
Abstract: Atmospheric ozone plays a key role in air quality and the radiation budget of the Earth, both directly and through its chemical influence on other trace gases. Assessments of the atmospheric ozone distribution and associated climate change therefore demand accurate vertically resolved ozone observations with both stratospheric and tropospheric sensitivity, on both global and regional scales, and both in the long term and at shorter timescales. Such observations have been acquired by two series of European nadir-viewing ozone profilers, namely the scattered-light UV-visible spectrometers of the GOME family, launched regularly since 1995 (GOME, SCIAMACHY, OMI, GOME-2A/B, TROPOMI, and the upcoming Sentinel-5 series), and the thermal infrared emission sounders of the IASI type, launched regularly since 2006 (IASI on Metop platforms and the upcoming IASI-NG on Metop-SG). In particular, several Level-2 retrieved, Level-3 monthly gridded, and Level-4 assimilated nadir ozone profile data products have been improved and harmonized in the context of the ozone project of the European Space Agency's Climate Change Initiative (ESA Ozone-cci). To verify their fitness for purpose, these ozone datasets must undergo a comprehensive quality assessment (QA), including (a) detailed identification of their geographical, vertical, and temporal domains of validity; (b) quantification of their potential bias, noise, and drift and their dependences on major influence quantities; and (c) assessment of the mutual consistency of data from different sounders. For this purpose we have applied to the Ozone-cci Climate Research Data Package (CRDP) released in 2017 the versatile QA and validation system Multi-TASTE, which has been developed in the context of several heritage projects (ESA's Multi-TASTE, EUMETSAT's O3M-SAF, and the European Commission's FP6 GEOmon and FP7 QA4ECV). This work, as the second in a series of four Ozone-cci validation papers, reports for the first time on data content studies, information content studies and ground-based validation for both the GOME- and IASI-type climate data records combined. The ground-based reference measurements have been provided by the Network for the Detection of Atmospheric Composition Change (NDACC), NASA's Southern Hemisphere Additional Ozonesonde programme (SHADOZ), and other ozonesonde and lidar stations contributing to the World Meteorological Organisation's Global Atmosphere Watch (WMO GAW). The nadir ozone profile CRDP quality assessment reveals that all nadir ozone profile products under study fulfil the GCOS user requirements in terms of observation frequency and horizontal and vertical resolution. Yet all L2 observations also show sensitivity outliers in the UTLS and are strongly correlated vertically due to substantial averaging kernel fluctuations that extend far beyond the kernel's 15km FWHM. The CRDP typically does not comply with the GCOS user requirements in terms of total uncertainty and decadal drift, except for the UV-visible L4 dataset. The drift values of the L2 GOME and OMI, the L3 IASI, and the L4 assimilated products are found to be overall insignificant, however, and applying appropriate altitude-dependent bias and drift corrections make the data fit for climate and atmospheric composition monitoring and modelling purposes. Dependence of the Ozone-cci data quality on major influence quantities - resulting in data screening suggestions to users - and perspectives for the Copernicus Sentinel missions are additionally discussed. © 2018 Copernicus GmbH. All rights reserved.
BibTeX:
@article{KeppensLambertGranvilleEtAl2018,
  author = {Keppens, A. and Lambert, J.-C. and Granville, J. and Hubert, D. and Verhoelst, T. and Compernolle, S. and Latter, B. and Kerridge, B. and Siddans, R. and Boynard, A. and Hadji-Lazaro, J. and Clerbaux, C. and Wespes, C. and Hurtmans, D.R. and Coheur, P.-F. and Van Peet, J.C.A. and Vander, R.J.A. and Garane, K. and Elissavet Koukouli, M. and Balis, D. and Delcloo, A. and Kivi, R. and Stübi, R. and Godin-Beekmann, S. and Van Roozendael, M. and Zehner, C.},
  title = {Quality assessment of the Ozone-cci Climate Research Data Package (release 2017) - Part 2: Ground-based validation of nadir ozone profile data products},
  journal = {Atmospheric Measurement Techniques},
  year = {2018},
  volume = {11},
  pages = {3769-3800},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043518277&doi=10.5194%2famt-11-3769-2018&partnerID=40&md5=9f930ed1a0d377f5a81370b610c5c86b},
  doi = {10.5194/amt-11-3769-2018}
}
Abstract: We use tropical observations of the water vapor isotopic composition, derived from IASI and TES spaceborne measurements, to show that the isotopic composition of water vapor in the free troposphere is sensitive to both the depth and the intensity of convection. We find that for any given precipitation intensity, vapor associated with deep convection is isotopically depleted relative to vapor associated with shallow convection. The intensity of precipitation also plays a role as for any given depth of convection, the relative enrichment of water vapor decreases as the intensity of precipitation increases. Shallow convection, via the uplifting of enriched boundary layer air into the free troposphere and the convective detrainment, enriches the free troposphere. In contrast, deep convection is associated with processes that deplete the water vapor in the free troposphere, such as rain re-evaporation. The results of this study allow for a better identification of the parameters controlling the isotopic composition of the free troposphere and indicate that the isotopic composition of water vapor can be used to evaluate the relative contributions of shallow and deep convection in global models. © 2017 Elsevier B.V.
BibTeX:
@article{LacourRisiWordenEtAl2018,
  author = {Lacour, J.-L. and Risi, C. and Worden, J. and Clerbaux, C. and Coheur, P.-F.},
  title = {Importance of depth and intensity of convection on the isotopic composition of water vapor as seen from IASI and TES δD observations},
  journal = {Earth and Planetary Science Letters},
  year = {2018},
  volume = {481},
  pages = {387-394},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033553775&doi=10.1016%2fj.epsl.2017.10.048&partnerID=40&md5=fa0cd93c1674232898b7a36fe2c3a2bf},
  doi = {10.1016/j.epsl.2017.10.048}
}
Abstract: Mobile in situ concentration and meteorology data were collected for the Chino Dairy Complex in the Los Angeles Basin by AMOG (AutoMObile trace Gas) Surveyor on 25 June 2015 to characterize husbandry emissions in the near and far field in convoy mode with MISTIR (Mobile Infrared Sensor for Tactical Incident Response), a mobile upwards-looking, column remote sensing spectrometer. MISTIR reference flux validated AMOG plume inversions at different information levels including multiple gases, GoogleEarth imagery, and airborne trace gas remote sensing data. Long-term (9-yr.) Infrared Atmospheric Sounding Interferometer satellite data provided spatial and trace gas temporal context. For the Chino dairies, MISTIR-AMOG ammonia (NH3) agreement was within 5% (15.7 versus 14.9 Gg yr−1, respectively) using all information. Methane (CH4) emissions were 30 Gg yr−1 for a 45,200 herd size, indicating that Chino emission factors are greater than previously reported. Single dairy inversions were much less successful. AMOG-MISTIR agreement was 57% due to wind heterogeneity from downwind structures in these near-field measurements and emissions unsteadiness. AMOG CH4, NH3, and CO2 emissions were 91, 209, and 8200 Mg yr−1, implying 2480, 1870, and 1720 head using published emission factors. Plumes fingerprinting identified likely sources including manure storage, cowsheds, and a structure with likely natural gas combustion. NH3 downwind of Chino showed a seasonal variation of a factor of ten, three times larger than literature suggests. Chino husbandry practices and trends in herd size and production were reviewed and unlikely to add seasonality. Higher emission seasonality was proposed as legacy soil emissions, the results of a century of husbandry, supported by airborne remote sensing data showing widespread emissions from neighborhoods that were dairies 15 years prior, and AMOG and MISTIR observations. Seasonal variations provide insights into the implications of global climate change and must be considered when comparing surveys from different seasons. Where sufficient information from multiple gases and number of likely sources, high emissions accuracy can be achieved for in situ data plume inversion. © 2018
BibTeX:
@article{LeiferMeltonTrattEtAl2018,
  author = {Leifer, I. and Melton, C. and Tratt, D.M. and Buckland, K.N. and Chang, C.S. and Frash, J. and Hall, J.L. and Kuze, A. and Leen, B. and Clarisse, L. and Lundquist, T. and Van Damme, M. and Vigil, S. and Whitburn, S. and Yurganov, L.},
  title = {Validation of mobile in situ measurements of dairy husbandry emissions by fusion of airborne/surface remote sensing with seasonal context from the Chino Dairy Complex},
  journal = {Environmental Pollution},
  year = {2018},
  pages = {2111-2134},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85049187867&doi=10.1016%2fj.envpol.2018.03.078&partnerID=40&md5=8c706d3265fd40b128c799d667c034e2},
  doi = {10.1016/j.envpol.2018.03.078}
}
Abstract: The Asian summer monsoon (ASM) creates a hemispheric-scale signature in trace-gas distributions in the upper troposphere and lower stratosphere (UTLS). Data from satellite retrievals are the best source of information for characterizing these large-scale signatures. Measurements from the Microwave Limb Sounder (MLS), a limb-viewing satellite sensor, have been the most widely used retrieval products for these types of studies. This work explores the information for the ASM influence on UTLS chemical distribution from two nadir-viewing sensors, the Infrared Atmospheric Sounding Interferometer (IASI) and the Ozone Monitoring Instrument (OMI), together with the MLS. Day-to-day changes in carbon monoxide (CO) and ozone (O3) tracer distributions in response to dynamical variability are examined to assess how well the data from different sensors provide useful information for studying the impact of sub-seasonal-scale dynamics on chemical fields. Our results, using June-August 2008 data, show that although the MLS provides relatively sparse horizontal sampling on daily timescales, interpolated daily CO distributions show a high degree of dynamical consistency with the synoptic-scale structure of and variability in the anticyclone. Our analysis also shows that the IASI CO retrieval has sufficient sensitivity to produce upper tropospheric (UT) CO with variabilities independent from the lower to middle tropospheric CO. The consistency of IASI CO field with the synoptic-scale anticyclone dynamical variability demonstrates that the IASI UT CO product is a physically meaningful dataset. Furthermore, IASI CO vertical cross sections combined with the daily maps provide the first observational evidence for a model analyses-based hypothesis on the preferred ASM vertical transport location and the subsequent horizontal redistribution via east-west eddy shedding. Similarly, the OMI O3 profile product is shown to be capable of distinguishing the tropospheric-dominated air mass in the anticyclone from the stratospheric-dominated background on a daily timescale, providing consistent and complementary information to the MLS. These results not only highlight the complementary information between nadir and limb sensors but also demonstrate the value of process-based retrieval evaluation for characterizing satellite data information content. © 2018 Copernicus GmbH. All rights reserved.
BibTeX:
@article{LuoPanHonomichlEtAl2018,
  author = {Luo, J. and Pan, L.L. and Honomichl, S.B. and Bergman, J.W. and Randel, W.J. and Francis, G. and Clerbaux, C. and George, M. and Liu, X. and Tian, W.},
  title = {Space-time variability in UTLS chemical distribution in the Asian summer monsoon viewed by limb and nadir satellite sensors},
  journal = {Atmospheric Chemistry and Physics},
  year = {2018},
  volume = {18},
  pages = {12511-12530},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052964153&doi=10.5194%2facp-18-12511-2018&partnerID=40&md5=43671e2e5f705fd541beac8edba82a10},
  doi = {10.5194/acp-18-12511-2018}
}
Abstract: Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2), which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD). Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl) alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2-particle-HCl processing and impacts following Sarychev Peak eruption, using the Community Earth System Model version 1.0 (CESM1) Whole Atmosphere Community Climate Model (WACCM)-Community Aerosol and Radiation Model for Atmospheres (CARMA) sectional aerosol microphysics model (with no a priori assumption on particle size). The Sarychev Peak 2009 eruption injected 0.9ĝ€Tg of SO2 into the upper troposphere and lower stratosphere (UTLS), enhancing the aerosol load in the Northern Hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to Infrared Atmospheric Sounding Interferometer (IASI) satellite data. Co-injection of 27ĝ€Ggĝ€†HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx) compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions such as Sarychev on stratospheric chemistry. The model-simulated evolution of effective radius (reff) reflects new particle formation followed by particle growth that enhances reff to reach up to 0.2ĝ€μm on zonal average. Comparisons of the model-simulated particle number and size distributions to balloon-borne in situ stratospheric observations over Kiruna, Sweden, in August and September 2009, and over Laramie, USA, in June and November 2009 show good agreement and quantitatively confirm the post-eruption particle enhancement. We show that the model-simulated SAOD is consistent with that derived from the Optical Spectrograph and InfraRed Imager System (OSIRIS) when both the saturation bias of OSIRIS and the fact that extinction profiles may terminate well above the tropopause are taken into account. Previous modelling studies (involving assumptions on particle size) that reported agreement with (biased) post-eruption estimates of SAOD derived from OSIRIS likely underestimated the climate impact of the 2009 Sarychev Peak eruption. © Author(s) 2018.
BibTeX:
@article{LurtonJegouBerthetEtAl2018,
  author = {Lurton, T. and Jégou, F. and Berthet, G. and Renard, J.-B. and Clarisse, L. and Schmidt, A. and Brogniez, C. and Roberts, T.J.},
  title = {Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2018},
  volume = {18},
  pages = {3223-3247},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043373813&doi=10.5194%2facp-18-3223-2018&partnerID=40&md5=e51b6b0b363bd14c234243f248c38318},
  doi = {10.5194/acp-18-3223-2018}
}
Abstract: Assessments of carbon monoxide emissions through inverse modeling are dependent on the modeled abundance of the hydroxyl radical (OH) which controls both the primary sink of CO and its photochemical source through hydrocarbon oxidation. However, most chemistry transport models (CTMs) fall short of reproducing constraints on hemispherically averaged OH levels derived from methylchloroform (MCF) observations. Here we construct five different OH fields compatible with MCF-based analyses, and we prescribe those fields in a global CTM to infer CO fluxes based on Infrared Atmospheric Sounding Interferometer (IASI) CO columns. Each OH field leads to a different set of optimized emissions. Comparisons with independent data (surface, ground-based remotely sensed, aircraft) indicate that the inversion adopting the lowest average OH level in the Northern Hemisphere (7.8 × 105 molec cm−3, ∼18% lower than the best estimate based on MCF measurements) provides the best overall agreement with all tested observation data sets. ©2018. The Authors.
BibTeX:
@article{MuellerStavrakouBauwensEtAl2018,
  author = {Müller, J.-F. and Stavrakou, T. and Bauwens, M. and George, M. and Hurtmans, D. and Coheur, P.-F. and Clerbaux, C. and Sweeney, C.},
  title = {Top-Down CO Emissions Based On IASI Observations and Hemispheric Constraints on OH Levels},
  journal = {Geophysical Research Letters},
  year = {2018},
  volume = {45},
  pages = {1621-1629},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041215056&doi=10.1002%2f2017GL076697&partnerID=40&md5=81cbaf24a8852001c033e64f75c812b5},
  doi = {10.1002/2017GL076697}
}
Abstract: Southeast Asia, in particular Indonesia, has periodically struggled with intense fire events. These events convert substantial amounts of carbon stored as peat to atmospheric carbon dioxide (CO2) and significantly affect atmospheric composition on a regional to global scale. During the recent 2015 El Niño event, peat fires led to strong enhancements of carbon monoxide (CO), an air pollutant and well-known tracer for biomass burning. These enhancements were clearly observed from space by the Infrared Atmospheric Sounding Interferometer (IASI) and the Measurements of Pollution in the Troposphere (MOPITT) instruments. We use these satellite observations to estimate CO fire emissions within an inverse modelling framework. We find that the derived CO emissions for each sub-region of Indonesia and Papua are substantially different from emission inventories, highlighting uncertainties in bottom-up estimates. CO fire emissions based on either MOPITT or IASI have a similar spatial pattern and evolution in time, and a 10% uncertainty based on a set of sensitivity tests we performed. Thus, CO satellite data have a high potential to complement existing operational fire emission estimates based on satellite observations of fire counts, fire radiative power and burned area, in better constraining fire occurrence and the associated conversion of peat carbon to atmospheric CO2. A total carbon release to the atmosphere of 0.35–0.60 Pg C can be estimated based on our results. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’. © 2018 The Authors.
BibTeX:
@article{Nechita-BandaKrolVanDerWerfEtAl2018,
  author = {Nechita-Banda, N. and Krol, M. and Van Der Werf, G.R. and Kaiser, J.W. and Pandey, S. and Huijnen, V. and Clerbaux, C. and Coheur, P. and Deeter, M.N. and Röckmann, T.},
  title = {Monitoring emissions from the 2015 Indonesian fires using CO satellite data},
  journal = {Philosophical Transactions of the Royal Society B: Biological Sciences},
  year = {2018},
  volume = {373},
  article number = {20170307},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054778339&doi=10.1098%2frstb.2017.0307&partnerID=40&md5=a03f0e019ea2dc55fbbf22d851cdae9a},
  doi = {10.1098/rstb.2017.0307}
}
Abstract: Data from Earth observation (EO) satellites are increasingly used to monitor the environment, understand variability and change, inform evaluations of climate model forecasts, and manage natural resources. Policymakers are progressively relying on the information derived from these datasets to make decisions on mitigating and adapting to climate change. These decisions should be evidence based, which requires confidence in derived products, as well as the reference measurements used to calibrate, validate, or inform product development. In support of the European Union's Earth Observation Programmes Copernicus Climate Change Service (C3S), the Quality Assurance for Essential Climate Variables (QA4ECV) project fulfilled a gap in the delivery of climate quality satellite-derived datasets, by prototyping a generic system for the implementation and evaluation of quality assurance (QA) measures for satellite-derived ECV climate data record products. The project demonstrated the QA system on six new long-term, climate quality ECV data records for surface albedo, leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FAPAR), nitrogen dioxide (NO2), formaldehyde (HCHO), and carbon monoxide (CO). The provision of standardised QA information provides data users with evidence-based confidence in the products and enables judgement on the fitness-for-purpose of various ECV data products and their specific applications. © 2018 by the authors.
BibTeX:
@article{NightingaleBoersmaMullerEtAl2018,
  author = {Nightingale, J. and Boersma, K.F. and Muller, J.-P. and Compernolle, S. and Lambert, J.-C. and Blessing, S. and Giering, R. and Gobron, N. and Smedt, I.D. and Coheur, P. and George, M. and Schulz, J. and Wood, A.},
  title = {Quality assurance framework development based on six new ECV data products to enhance user confidence for climate applications},
  journal = {Remote Sensing},
  year = {2018},
  volume = {10},
  article number = {1254},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051660709&doi=10.3390%2frs10081254&partnerID=40&md5=a5cc78942c6f38d4ce159875de5478e9},
  doi = {10.3390/rs10081254}
}
Abstract: This study aims to understand the spatial and temporal variability of HNO3 total columns in terms of explanatory variables. To achieve this, multiple linear regressions are used to fit satellite-derived time series of HNO3 daily averaged total columns. First, an analysis of the IASI 9-year time series (2008-2016) is conducted based on various equivalent latitude bands. The strong and systematic denitrification of the southern polar stratosphere is observed very clearly. It is also possible to distinguish, within the polar vortex, three regions which are differently affected by the denitrification. Three exceptional denitrification episodes in 2011, 2014 and 2016 are also observed in the Northern Hemisphere, due to unusually low arctic temperatures. The time series are then fitted by multivariate regressions to identify what variables are responsible for HNO3 variability in global distributions and time series, and to quantify their respective influence. Out of an ensemble of proxies (annual cycle, solar flux, quasi-biennial oscillation, multivariate ENSO index, Arctic and Antarctic oscillations and volume of polar stratospheric clouds), only the those defined as significant (p value<0.05) by a selection algorithm are retained for each equivalent latitude band. Overall, the regression gives a good representation of HNO3 variability, with especially good results at high latitudes (60-80% of the observed variability explained by the model). The regressions show the dominance of annual variability in all latitudinal bands, which is related to specific chemistry and dynamics depending on the latitudes. We find that the polar stratospheric clouds (PSCs) also have a major influence in the polar regions, and that their inclusion in the model improves the correlation coefficients and the residuals. However, there is still a relatively large portion of HNO3 variability that remains unexplained by the model, especially in the intertropical regions, where factors not included in the regression model (such as vegetation fires or lightning) may be at play. © 2018 Author(s).
BibTeX:
@article{RonsmansWespesHurtmansEtAl2018,
  author = {Ronsmans, G. and Wespes, C. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {Spatio-temporal variations of nitric acid total columns from 9 years of IASI measurements-A driver study},
  journal = {Atmospheric Chemistry and Physics},
  year = {2018},
  volume = {18},
  pages = {4403-4423},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044964344&doi=10.5194%2facp-18-4403-2018&partnerID=40&md5=f195fc15306aed752d04c7e53d1d6180},
  doi = {10.5194/acp-18-4403-2018}
}
Abstract: The chemistry-climate model ECHAM-HAMMOZ contains a detailed representation of tropospheric and stratospheric reactive chemistry and state-of-the-art parameterizations of aerosols using either a modal scheme (M7) or a bin scheme (SALSA). This article describes and evaluates the model version ECHAM6.3-HAM2.3-MOZ1.0 with a focus on the tropospheric gas-phase chemistry. A 10-year model simulation was performed to test the stability of the model and provide data for its evaluation. The comparison to observations concentrates on the year 2008 and includes total column observations of ozone and CO from IASI and OMI, Aura MLS observations of temperature, HNO3, ClO, and O3 for the evaluation of polar stratospheric processes, an ozonesonde climatology, surface ozone observations from the TOAR database, and surface CO data from the Global Atmosphere Watch network. Global budgets of ozone, OH, NOx, aerosols, clouds, and radiation are analyzed and compared to the literature. ECHAM-HAMMOZ performs well in many aspects. However, in the base simulation, lightning NOx emissions are very low, and the impact of the heterogeneous reaction of HNO3 on dust and sea salt aerosol is too strong. Sensitivity simulations with increased lightning NOx or modified heterogeneous chemistry deteriorate the comparison with observations and yield excessively large ozone budget terms and too much OH. We hypothesize that this is an impact of potential issues with tropical convection in the ECHAM model. © 2018 Author(s).
BibTeX:
@article{SchultzStadtlerSchroederEtAl2018,
  author = {Schultz, M.G. and Stadtler, S. and Schröder, S. and Taraborrelli, D. and Franco, B. and Krefting, J. and Henrot, A. and Ferrachat, S. and Lohmann, U. and Neubauer, D. and Siegenthaler-Le Drian, C. and Wahl, S. and Kokkola, H. and Kühn, T. and Rast, S. and Schmidt, H. and Stier, P. and Kinnison, D. and Tyndall, G.S. and Orlando, J.J. and Wespes, C.},
  title = {The chemistry-climate model ECHAM6.3-HAM2.3-MOZ1.0},
  journal = {Geoscientific Model Development},
  year = {2018},
  volume = {11},
  pages = {1695-1723},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046833399&doi=10.5194%2fgmd-11-1695-2018&partnerID=40&md5=c06d5a7291cc76359cb95bbcbee6e25a},
  doi = {10.5194/gmd-11-1695-2018}
}
Abstract: Satellite remote sensing of the Earth's atmospheric composition usually samples irregularly in space and time, and many applications require spatially and temporally averaging the satellite observations (level 2) to a regular grid (level 3). When averaging level 2 data over a long period to a target level 3 grid that is significantly finer than the sizes of level 2 pixels, this process is referred to as. An agile, physics-based oversampling approach is developed to represent each satellite observation as a sensitivity distribution on the ground, instead of a point or a polygon as assumed in previous methods. This sensitivity distribution can be determined by the spatial response function of each satellite sensor. A generalized 2-D super Gaussian function is proposed to characterize the spatial response functions of both imaging grating spectrometers (e.g., OMI, OMPS, and TROPOMI) and scanning Fourier transform spectrometers (e.g., GOSAT, IASI, and CrIS). Synthetic OMI and IASI observations were generated to compare the errors due to simplifying satellite fields of view (FOVs) as polygons (tessellation error) and the errors due to discretizing the smooth spatial response function on a finite grid (discretization error). The balance between these two error sources depends on the target grid size, the ground size of the FOV, and the smoothness of spatial response functions. Explicit consideration of the spatial response function is favorable for fine-grid oversampling and smoother spatial response. For OMI, it is beneficial to oversample using the spatial response functions for grids finer than ∼ 16 km. The generalized 2-D super Gaussian function also enables smoothing of the level 3 results by decreasing the shape-determining exponents, which is useful for a high noise level or sparse satellite datasets. This physical oversampling approach is especially advantageous during smaller temporal windows and shows substantially improved visualization of trace gas distribution and local gradients when applied to OMI NO2 products and IASI NH3 products. There is no appreciable difference in the computational time when using the physical oversampling versus other oversampling methods. © 2018 Author(s).
BibTeX:
@article{SunZhuCady-PereiraEtAl2018,
  author = {Sun, K. and Zhu, L. and Cady-Pereira, K. and Chan Miller, C. and Chance, K. and Clarisse, L. and Coheur, P.-F. and González Abad, G. and Huang, G. and Liu, X. and Van Damme, M. and Yang, K. and Zondlo, M.},
  title = {A physics-based approach to oversample multi-satellite, multispecies observations to a common grid},
  journal = {Atmospheric Measurement Techniques},
  year = {2018},
  volume = {11},
  pages = {6679-6701},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058947009&doi=10.5194%2famt-11-6679-2018&partnerID=40&md5=ddd79106196fc794e98829c0f701a175},
  doi = {10.5194/amt-11-6679-2018}
}
Abstract: Through its important role in the formation of particulate matter, atmospheric ammonia affects air quality and has implications for human health and life expectancy1,2. Excess ammonia in the environment also contributes to the acidification and eutrophication of ecosystems3–5 and to climate change6. Anthropogenic emissions dominate natural ones and mostly originate from agricultural, domestic and industrial activities7. However, the total ammonia budget and the attribution of emissions to specific sources remain highly uncertain across different spatial scales7–9. Here we identify, categorize and quantify the world’s ammonia emission hotspots using a high-resolution map of atmospheric ammonia obtained from almost a decade of daily IASI satellite observations. We report 248 hotspots with diameters smaller than 50 kilometres, which we associate with either a single point source or a cluster of agricultural and industrial point sources—with the exception of one hotspot, which can be traced back to a natural source. The state-of-the-art EDGAR emission inventory10 mostly agrees with satellite-derived emission fluxes within a factor of three for larger regions. However, it does not adequately represent the majority of point sources that we identified and underestimates the emissions of two-thirds of them by at least one order of magnitude. Industrial emitters in particular are often found to be displaced or missing. Our results suggest that it is necessary to completely revisit the emission inventories of anthropogenic ammonia sources and to account for the rapid evolution of such sources over time. This will lead to better health and environmental impact assessments of atmospheric ammonia and the implementation of suitable nitrogen management strategies. © 2018, Springer Nature Limited.
BibTeX:
@article{VanDammeClarisseWhitburnEtAl2018,
  author = {Van Damme, M. and Clarisse, L. and Whitburn, S. and Hadji-Lazaro, J. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {Industrial and agricultural ammonia point sources exposed},
  journal = {Nature},
  year = {2018},
  volume = {564},
  pages = {99-103},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057725598&doi=10.1038%2fs41586-018-0747-1&partnerID=40&md5=0cf214576e7191348a44b7c0745f16ec},
  doi = {10.1038/s41586-018-0747-1}
}
Abstract: Enhanced mitigation of short-lived climate pollutants (SLCPs) has been recently paid more attention in order to provide more sizeable short-term reductions of global warming effects over the next several decades. We overview in this article our recent progress in the development of spectroscopic instruments for optical monitoring of major SLCPs based on laser absorption spectroscopy. Methane (CH4) and black carbon (BC) are the most important SLCPs contributing to the human enhancement of the global greenhouse effect after CO2. We present optical sensing of these two climate-change related atmospheric species to illustrate how “classical” spectroscopy can help to address today's challenging issues: (1) Photoacoustic measurements of BC optical absorption coefficient in order to determine its radiative-forcing related optical parameters (such as mass absorption coefficient, absorption Ångström coefficient) with higher precision (∼7.4% compared to 12–30% for filter-based methods routinely used nowadays). The 1σ (SNR = 1) minimum measurable volumetric mass density of 21 ng/m3 (in 60 s) for black carbon. (2) Direct absorption spectroscopy-based monitoring of methane (CH4) in field campaign to identify pollution source in conjunction with air mass back-trajectory modeling. Using a White‐type multipass cell (an effective path‐length of 175 m), a 1σ detection limit of 33.3 ppb in 218 s was achieved with a relative measurement precision of 1.1% and an overall measurement uncertainty of about 5.1%. Performance of the custom, lab-based instruments (in terms of detection limits, measurement precision, temporal response, etc.), spectroscopic measurement aspects, experimental details, spectral data processing, analysis and modeling of the observed environmental episode will be presented and discussed. © 2018 Elsevier Inc.
BibTeX:
@article{WangShenYiEtAl2018,
  author = {Wang, G. and Shen, F. and Yi, H. and Hubert, P. and Deguine, A. and Petitprez, D. and Maamary, R. and Augustin, P. and Fourmentin, M. and Fertein, E. and Sigrist, M.W. and Ba, T.-N. and Chen, W.},
  title = {Laser absorption spectroscopy applied to monitoring of short-lived climate pollutants (SLCPs)},
  journal = {Journal of Molecular Spectroscopy},
  year = {2018},
  volume = {348},
  pages = {142-151},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045019815&doi=10.1016%2fj.jms.2018.03.015&partnerID=40&md5=8b566c21b200a799fb1f6aeda15d84b4},
  doi = {10.1016/j.jms.2018.03.015}
}
Abstract: In this study, we describe the recent changes in the tropospheric ozone (O3) columns measured by the Infrared Atmospheric Sounding Interferometer (IASI), onboard the Metop satellite, during the first 9 years of operation (January 2008 to May 2017). Using appropriate multivariate regression methods, we differentiate significant linear trends from other sources of O3 variations captured by IASI. The geographical patterns of the adjusted O3 trends are provided and discussed on the global scale. Given the large contribution of the natural variability in comparison with that of the trend (25-85% vs. 15-50%, respectively) to the total O3 variations, we estimate that additional years of IASI measurements are generally required to detect the estimated O3 trends with high precision. Globally, additional 6 months to 6 years of measurements, depending on the regions and the seasons, are needed to detect a trend of |5|DUdecadeg-1. An exception is interestingly found during summer at mid-and high latitudes of the Northern Hemisphere (NH; ∼ 40 to ∼75°N), where the large absolute fitted trend values (∼ |0.5|DUyrg-1 on average) combined with the small model residuals (∼ 10%) allow for detection of a band-like pattern of significant negative trends. Despite no consensus in terms of tropospheric O3 trends having been reached from the available independent datasets (UV or IR satellites, O3 sondes, aircrafts, ground-based measurements, etc.) for the reasons that are discussed in the text, this finding is consistent with the reported decrease in O3 precursor emissions in recent years, especially in Europe and USA. The influence of continental pollution on that latitudinal band is further investigated and supported by the analysis of the O3-CO relationship (in terms of correlation coefficient, regression slope and covariance) that we found to be the strongest at northern midlatitudes in summer. © 2018 Author(s).
BibTeX:
@article{WespesHurtmansClerbauxEtAl2018,
  author = {Wespes, C. and Hurtmans, D. and Clerbaux, C. and Boynard, A. and Coheur, P.-F.},
  title = {Decrease in tropospheric O3 levels in the Northern Hemisphere observed by IASI},
  journal = {Atmospheric Chemistry and Physics},
  year = {2018},
  volume = {18},
  pages = {6867-6885},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047489181&doi=10.5194%2facp-18-6867-2018&partnerID=40&md5=9ea69bd4aa2b7d9aef1154aeccdcdd48},
  doi = {10.5194/acp-18-6867-2018}
}
Abstract: Separating concentrations of carbon monoxide (CO) in the boundary layer from the rest of the atmosphere with nadir satellite measurements is of particular importance to differentiate emission from transport. Although thermal infrared (TIR) satellite sounders are considered to have limited sensitivity to the composition of the near-surface atmosphere, previous studies show that they can provide information on CO close to the ground in case of high thermal contrast. In this work we investigate the capability of IASI (Infrared Atmospheric Sounding Interferometer) to retrieve near-surface CO concentrations, and we quantitatively assess the influence of thermal contrast on such retrievals. We present a 3-part analysis, which relies on both theoretical forward simulations and retrievals on real data, performed for a large range of negative and positive thermal contrast situations. First, we derive theoretically the IASI detection threshold of CO enhancement in the boundary layer, and we assess its dependence on thermal contrast. Then, using the optimal estimation formalism, we quantify the role of thermal contrast on the error budget and information content of near-surface CO retrievals. We demonstrate that, contrary to what is usually accepted, large negative thermal contrast values (ground cooler than air) lead to a better decorrelation between CO concentrations in the low and the high troposphere than large positive thermal contrast (ground warmer than the air). In the last part of the paper we use Mexico City and Barrow as test cases to contrast our theoretical predictions with real retrievals, and to assess the accuracy of IASI surface CO retrievals through comparisons to ground-based in-situ measurements. © 2017 Elsevier Ltd
BibTeX:
@article{BauduinClarisseTheunissenEtAl2017,
  author = {Bauduin, S. and Clarisse, L. and Theunissen, M. and George, M. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {IASI's sensitivity to near-surface carbon monoxide (CO): Theoretical analyses and retrievals on test cases},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2017},
  volume = {189},
  pages = {428-440},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008470444&doi=10.1016%2fj.jqsrt.2016.12.022&partnerID=40&md5=aab17593b899a20fcdb33f7731304466},
  doi = {10.1016/j.jqsrt.2016.12.022}
}
Abstract: After 43 years of inactivity, the Calbuco volcano, which is located in the southern part of Chile, erupted on 22 April 2015. The space-time evolutions (distribution and transport) of its aerosol plume are investigated by combining satellite (CALIOP, IASI, OMPS), in situ aerosol counting (LOAC OPC) and lidar observations, and the MIMOSA advection model. The Calbuco aerosol plume reached the Indian Ocean 1 week after the eruption. Over the Reunion Island site (21 S, 55.5 E), the aerosol signal was unambiguously enhanced in comparison with "background" conditions, with a volcanic aerosol layer extending from 18 to 21 km during the May-July period. All the data reveal an increase by a factor of 2 in the SAOD (stratospheric aerosol optical depth) with respect to values observed before the eruption. The aerosol mass e-folding time is approximately 90 days, which is rather close to the value (80 days) reported for the Sarychev eruption. Microphysical measurements obtained before, during, and after the eruption reflecting the impact of the Calbuco eruption on the lower stratospheric aerosol content have been analyzed over the Reunion Island site. During the passage of the plume, the volcanic aerosol was characterized by an effective radius of 0.160.02 μm with a unimodal size distribution for particles above 0.2 μm in diameter. Particle concentrations for sizes larger than 1 μm are too low to be properly detected by the LOAC OPC. The aerosol number concentration was 20 times higher that observed before and 1 year after the eruption. According to OMPS and lidar observations, a tendency toward conditions before the eruption was observed by April 2016. The volcanic aerosol plume is advected eastward in the Southern Hemisphere and its latitudinal extent is clearly bounded by the subtropical barrier and the polar vortex. The transient behavior of the aerosol layers observed above Reunion Island between May and July 2015 reflects an inhomogeneous spatio-temporal distribution of the plume, which is controlled by the localization of these dynamical barriers. © Author(s) 2017.
BibTeX:
@article{BegueVignellesBerthetEtAl2017,
  author = {Bègue, N. and Vignelles, D. and Berthet, G. and Portafaix, T. and Payen, G. and Jégou, F. and Benchérif, H. and Jumelet, J. and Lurton, T. and Renard, J.-B. and Clarisse, L. and Duverger, V. and Posny, F. and Metzger, J.-M. and Godin-Beekmann, S.},
  title = {Long-range transport of stratospheric aerosols in the Southern Hemisphere following the 2015 Calbuco eruption},
  journal = {Atmospheric Chemistry and Physics},
  year = {2017},
  volume = {17},
  pages = {15019-15036},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029520896&doi=10.5194%2facp-17-15019-2017&partnerID=40&md5=dd97748ce2ba56d8c9c510746da19737},
  doi = {10.5194/acp-17-15019-2017}
}
Abstract: In order to recognize the importance of ozone (O3) in the troposphere and lower stratosphere in the tropics, a DIAL (differential absorption lidar) tropospheric O3 lidar system (LIO3TUR) was developed and installed at the Université de la Réunion campus site (close to the sea) on Reunion Island (southern tropics) in 1998. From 1998 to 2010, it acquired 427 O3 profiles from the low to the upper troposphere and has been central to several studies. In 2012, the system was moved up to the new Maïdo Observatory facility (2160-l. - metres above mean sea level) where it started operation in February 2013. The current system (LIO3T) configuration generates a 266 beam obtained with the fourth harmonic of a Nd:YAG laser sent into a Raman cell filled up with deuterium (using helium as buffer gas), generating the 289 and 316 beams to enable the use of the DIAL method for O3 profile measurements. The optimal range for the actual system is 6-19ga.m.s.l., depending on the instrumental and atmospheric conditions. For a 1gh integration time, vertical resolution varies from 0.7gkm at 6ga.m.s.l. to 1.3gkm at 19ga.m.s.l., and mean uncertainty within the 6-19gkm range is between 6 and 13g%. Comparisons with eight electrochemical concentration cell (ECC) sondes simultaneously launched from the Maïdo Observatory show good agreement between data sets with a 6.8g% mean absolute relative difference (D) between 6 and 17ga.m.s.l. (LIO3T lower than ECC). Comparisons with 37 ECC sondes launched from the nearby Gillot site during the daytime in a ±24gh window around lidar shooting result in a 9.4g% D between 6 and 19ga.m.s.l. (LIO3T lower than ECC). Comparisons with 11 ground-based Network for Detection of Atmospheric Composition Change (NDACC) Fourier transform infrared (FTIR) spectrometer measurements acquired during the daytime in a ±24gh window around lidar shooting show good agreement between data sets with a D of 11.8g% for the 8.5-16gkm partial column (LIO3T higher than FTIR), and comparisons with 39 simultaneous Infrared Atmospheric Sounding Interferometer (IASI) observations over Reunion Island show good agreement between data sets with a D of 11.3g% for the 6-16gkm partial column (LIO3T higher than IASI). ECC, LIO3TUR and LIO3T O3 monthly climatologies all exhibit the same range of values and patterns. In particular, the Southern Hemisphere biomass burning seasonal enhancement and the ozonopause altitude decrease in late austral winter-spring, as well as the sign of deep convection bringing boundary layer O3-poor air masses up to the middle-upper troposphere in late austral summer, are clearly visible in all data sets. © Author(s) 2017.
BibTeX:
@article{DuflotBarayPayenEtAl2017,
  author = {Duflot, V. and Baray, J.-L. and Payen, G. and Marquestaut, N. and Posny, F. and Metzger, J.-M. and Langerock, B. and Vigouroux, C. and Hadji-Lazaro, J. and Portafaix, T. and De Mazière, M. and Coheur, P.-F. and Clerbaux, C. and Cammas, J.-P.},
  title = {Tropospheric ozone profiles by DIAL at Maïdo Observatory (Reunion Island): System description, instrumental performance and result comparison with ozone external data set},
  journal = {Atmospheric Measurement Techniques},
  year = {2017},
  volume = {10},
  pages = {3359-3373},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029471830&doi=10.5194%2famt-10-3359-2017&partnerID=40&md5=3c0b2be1d7229feedb0a326b68233eaa},
  doi = {10.5194/amt-10-3359-2017}
}
Abstract: The isotopic composition of water vapour in the North Atlantic free troposphere is investigated with Infrared Atmospheric Sounding Interferometer (IASI) measurements of the D/H ratio (δD) above the ocean. We show that in the vicinity of West Africa, the seasonality of δD is particularly strong (130 ‰), which is related with the influence of the Saharan heat low (SHL) during summertime. The SHL indeed largely influences the dynamic in that region by producing deep turbulent mixing layers, yielding a specific water vapour isotopic footprint. The influence of the SHL on the isotopic budget is analysed on various time and space scales and is shown to be large, highlighting the importance of the SHL dynamics on the moistening and the HDO enrichment of the free troposphere over the North Atlantic. The potential influence of the SHL is also investigated on the inter-annual scale as we also report important variations in δD above the Canary archipelago region. We interpret the variability in the enrichment, using backward trajectory analyses, in terms of the ratio of air masses coming from the North Atlantic and air masses coming from the African continent. Finally, the interest of IASI high sampling capabilities is further illustrated by presenting spatial distributions of δD and humidity above the North Atlantic from which we show that the different sources and dehydration pathways controlling the humidity can be disentangled thanks to the added value of δD observations. More generally, our results demonstrate the utility of δD observations obtained from the IASI sounder to gain insight into the hydrological cycle processes in the West African region. © Author(s) 2017.
BibTeX:
@article{LacourFlamantRisiEtAl2017,
  author = {Lacour, J.-L. and Flamant, C. and Risi, C. and Clerbaux, C. and Coheur, P.-F.},
  title = {Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δd observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2017},
  volume = {17},
  pages = {9645-9663},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027345345&doi=10.5194%2facp-17-9645-2017&partnerID=40&md5=d86dabff56b3c699ca81327e697adb52},
  doi = {10.5194/acp-17-9645-2017}
}
Abstract: Methane (CH4) and ammonia (NH3) directly and indirectly affect the atmospheric radiative balance with the latter leading to aerosol generation. Both have important spectral features in the Thermal InfraRed (TIR) that can be studied by remote sensing, with NH3allowing discrimination of husbandry from other CH4sources. Airborne hyperspectral imagery was collected for the Chino Dairy Complex in the Los Angeles Basin as well as in situ CH4, carbon dioxide (CO2) and NH3data. TIR data showed good spatial agreement with in situ measurements and showed significant emissions heterogeneity between dairies. Airborne remote sensing mapped plume transport for ∼20 km downwind, documenting topographic effects on plume advection. Repeated multiple gas in situ measurements showed that emissions were persistent on half-year timescales. Inversion of one dairy plume found annual emissions of 4.1 × 105 kg CH4, 2.2 × 105 kg NH3, and 2.3 × 107 kg CO2, suggesting 2300, 4000, and 2100 head of cattle, respectively, and Chino Dairy Complex emissions of 42 Gg CH4and 8.4 Gg NH3implying ∼200k cows, ∼30% more than Peischl et al. (2013) estimated for June 2010. Far-field data showed chemical conversion and/or deposition of Chino NH3occurs within the confines of the Los Angeles Basin on a four to six h timescale, faster than most published rates, and likely from higher Los Angeles oxidant loads. Satellite observations from 2011 to 2014 confirmed that observed in situ transport patterns were representative and suggests much of the Chino Dairy Complex emissions are driven towards eastern Orange County, with a lesser amount transported to Palm Springs, CA. Given interest in mitigating husbandry health impacts from air pollution emissions, this study highlights how satellite observations can be leveraged to understand exposure and how multiple gas in situ emissions studies can inform on best practices given that emissions reduction of one gas could increase those of others. © 2016 Elsevier Ltd
BibTeX:
@article{LeiferMeltonTrattEtAl2017,
  author = {Leifer, I. and Melton, C. and Tratt, D.M. and Buckland, K.N. and Clarisse, L. and Coheur, P. and Frash, J. and Gupta, M. and Johnson, P.D. and Leen, J.B. and Van Damme, M. and Whitburn, S. and Yurganov, L.},
  title = {Remote sensing and in situ measurements of methane and ammonia emissions from a megacity dairy complex: Chino, CA},
  journal = {Environmental Pollution},
  year = {2017},
  volume = {221},
  pages = {37-51},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008350824&doi=10.1016%2fj.envpol.2016.09.083&partnerID=40&md5=6d0878868bdca6580033f3b6b292ea8b},
  doi = {10.1016/j.envpol.2016.09.083}
}
Abstract: Concentrated agricultural activities and animal feeding operations in the northeastern plains of Colorado represent an important source of atmospheric ammonia (NH3). The NH3 from these sources contributes to regional fine particle formation and to nitrogen deposition to sensitive ecosystems in Rocky Mountain National Park (RMNP), located ∼80 km to the west. In order to better understand temporal and spatial differences in NH3 concentrations in this source region, weekly concentrations of NH3 were measured at 14 locations during the summers of 2010 to 2015 using Radiello passive NH3 samplers. Weekly (biweekly in 2015) average NH3 concentrations ranged from 2.66 to 42.7μ-3, with the highest concentrations near large concentrated animal feeding operations (CAFOs). The annual summertime mean NH3 concentrations were stable in this region from 2010 to 2015, providing a baseline against which concentration changes associated with future changes in regional NH3 emissions can be assessed. Vertical profiles of NH3 were also measured on the 300 m Boulder Atmospheric Observatory (BAO) tower throughout 2012. The highest NH3 concentration along the vertical profile was always observed at the 10 m height (annual average concentration of 4.63 μgm-3), decreasing toward the surface (4.35g μg-3) and toward higher altitudes (1.93g μg-3). The NH3 spatial distributions measured using the passive samplers are compared with NH3 columns retrieved by the Infrared Atmospheric Sounding Interferometer (IASI) satellite and concentrations simulated by the Comprehensive Air Quality Model with Extensions (CAMx). The satellite comparison adds to a growing body of evidence that IASI column retrievals of NH3 provide very useful insight into regional variability in atmospheric NH3, in this case even in a region with strong local sources and sharp spatial gradients. The CAMx comparison indicates that the model does a reasonable job simulating NH3 concentrations near sources but tends to underpredict concentrations at locations farther downwind. Excess NH3 deposition by the model is hypothesized as a possible explanation for this trend. © 2017 Author(s).
BibTeX:
@article{LiThompsonVanDammeEtAl2017,
  author = {Li, Y. and Thompson, T.M. and Van Damme, M. and Chen, X. and Benedict, K.B. and Shao, Y. and Day, D. and Boris, A. and Sullivan, A.P. and Ham, J. and Whitburn, S. and Clarisse, L. and Coheur, P.-F. and Collett, J.L.},
  title = {Temporal and spatial variability of ammonia in urban and agricultural regions of northern Colorado, United States},
  journal = {Atmospheric Chemistry and Physics},
  year = {2017},
  volume = {17},
  pages = {6197-6213},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020394434&doi=10.5194%2facp-17-6197-2017&partnerID=40&md5=8b54bd78924f0b7de875caa26405dff5},
  doi = {10.5194/acp-17-6197-2017}
}
Abstract: It is in the early 1950s that researchers from the University of Liège started to investigate the Earth's atmosphere from the Jungfraujoch scientific station, in the Swiss Alps, at a time when concerns related to atmospheric composition changes were nonexistent. Since then, a worldwide unique infrared observational data base has been carefully collected. The exploitation of these observations has allowed constituting multi-decadal time series crucial for the characterization of the changes that affected our atmosphere and for the identification of their causes. In this paper, we first remind about the successive steps which led to establishing the observational program of the Liège team at the Jungfraujoch and we evoke important findings which justified its continuation. Then we present some recent results relevant to the Montreal and Kyoto Protocols, or related to the monitoring of air quality. © 2017 Societe Geographique de Liege. All rights reserved.
BibTeX:
@article{MahieuBaderBovyEtAl2017,
  author = {Mahieu, E. and Bader, W. and Bovy, B. and Demoulin, P. and Flock, O. and Franco, B. and Lejeune, B. and Prignon, M. and Roland, G. and Servais, C.},
  title = {Monitoring of the earth's atmosphere from the Jungfraujoch station: A journey started by the Liège team is more than 65 years! [Surveillance De L'atmosphère Terrestre Depuis La Station Du Jungfraujoch : Une Épopée Liégeoise Entamée Voici Plus De 65 Ans !]},
  journal = {BSGLg},
  year = {2017},
  volume = {68},
  pages = {119-130},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044320497&partnerID=40&md5=9cb3ce431531e42b39ed4714b3f4d27b}
}
Abstract: Aerosols have a potentially large effect on climate, particularly through their interactions with clouds, but the magnitude of this effect is highly uncertain. Large volcanic eruptions produce sulfur dioxide, which in turn produces aerosols; these eruptions thus represent a natural experiment through which to quantify aerosol-cloud interactions. Here we show that the massive 2014-2015 fissure eruption in Holuhraun, Iceland, reduced the size of liquid cloud droplets - consistent with expectations - but had no discernible effect on other cloud properties. The reduction in droplet size led to cloud brightening and global-mean radiative forcing of around -0.2 watts per square metre for September to October 2014. Changes in cloud amount or cloud liquid water path, however, were undetectable, indicating that these indirect effects, and cloud systems in general, are well buffered against aerosol changes. This result will reduce uncertainties in future climate projections, because we are now able to reject results from climate models with an excessive liquid-water-path response. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
BibTeX:
@article{MalavelleHaywoodJonesEtAl2017,
  author = {Malavelle, F.F. and Haywood, J.M. and Jones, A. and Gettelman, A. and Clarisse, L. and Bauduin, S. and Allan, R.P. and Karset, I.H.H. and Kristjánsson, J.E. and Oreopoulos, L. and Cho, N. and Lee, D. and Bellouin, N. and Boucher, O. and Grosvenor, D.P. and Carslaw, K.S. and Dhomse, S. and Mann, G.W. and Schmidt, A. and Coe, H. and Hartley, M.E. and Dalvi, M. and Hill, A.A. and Johnson, B.T. and Johnson, C.E. and Knight, J.R. and O'Connor, F.M. and Stier, P. and Myhre, G. and Platnick, S. and Stephens, G.L. and Takahashi, H. and Thordarson, T.},
  title = {Strong constraints on aerosol-cloud interactions from volcanic eruptions},
  journal = {Nature},
  year = {2017},
  volume = {546},
  pages = {485-491},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85021083991&doi=10.1038%2fnature22974&partnerID=40&md5=656012bebd58bf9b0834de67b4d904de},
  doi = {10.1038/nature22974}
}
Abstract: Emission of volcanic gas is thought to be the dominant process by which volatiles transit from the deep earth to the atmosphere. Volcanic gas emissions, remain poorly constrained, and volcanoes of Peru are entirely absent from the current global dataset. In Peru, Sabancaya and Ubinas volcanoes are by far the largest sources of volcanic gas. Here, we report the first measurements of the compositions and fluxes of volcanic gases emitted from these volcanoes. The measurements were acquired in November 2015. We determined an average SO2 flux of 15.3 ± 2.3 kg s− 1 (1325-ton day− 1) at Sabancaya and of 11.4 ± 3.9 kg s− 1 (988-ton day− 1) at Ubinas using scanning ultraviolet spectroscopy and dual UV camera systems. In-situ Multi-GAS analyses yield molar proportions of H2O, CO2, SO2, H2S and H2 gases of 73, 15, 10 1.15 and 0.15 mol% at Sabancaya and of 96, 2.2, 1.2 and 0.05 mol% for H2O, CO2, SO2 and H2S at Ubinas. Together, these data imply cumulative fluxes for both volcanoes of 282, 30, 27, 1.2 and 0.01 kg s− 1 of H2O, CO2, SO2, H2S and H2 respectively. Sabancaya and Ubinas volcanoes together contribute about 60% of the total CO2 emissions from the Central Volcanic zone, and dominate by far the total revised volatile budget of the entire Central Volcanic Zone of the Andes. © 2017 Elsevier B.V.
BibTeX:
@article{MoussallamTamburelloPetersEtAl2017,
  author = {Moussallam, Y. and Tamburello, G. and Peters, N. and Apaza, F. and Schipper, C.I. and Curtis, A. and Aiuppa, A. and Masias, P. and Boichu, M. and Bauduin, S. and Barnie, T. and Bani, P. and Giudice, G. and Moussallam, M.},
  title = {Volcanic gas emissions and degassing dynamics at Ubinas and Sabancaya volcanoes; implications for the volatile budget of the central volcanic zone},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2017},
  volume = {343},
  pages = {181-191},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85021701991&doi=10.1016%2fj.jvolgeores.2017.06.027&partnerID=40&md5=4ee1f7b7f28a0b2ae16706dc9fdd0a3b},
  doi = {10.1016/j.jvolgeores.2017.06.027}
}
Abstract: Satellite-derived enhancement ratios of NH3 relative to CO column burden (ERNH3/CO) in fires over Alaska, the Amazon, and South Equatorial Africa are 35, 45, and 70% lower than the corresponding ratio of their emissions factors (ERNH3/CO) from biomass burning derived from in situ observations. Simulations performed using the Geophysical Fluid Dynamics Laboratory AM3 global chemistry-climate model show that these regional differences may not entirely stem from an overestimate of NH3 emissions but rather from changes in the gas-aerosol partitioning of NH3 to NH4+. Differences between (ERNH3/CO) and (EFNH3/CO) are largest in regions where is high, consistent with the production of NH4NO3. Biomass burning is estimated to contribute 11–23% of the global burden and direct radiative effect (DRE) of NH4NO3 (−15 to −28 mW m−2), despite accounting for less than 6% of the global source of NH3. Production of NH4NO3 is largely concentrated over the Amazon and South Equatorial Africa, where its DRE can reach −1.9 W m−2 during the biomass burning season. ©2017. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{PaulotPaynterGinouxEtAl2017,
  author = {Paulot, F. and Paynter, D. and Ginoux, P. and Naik, V. and Whitburn, S. and Van Damme, M. and Clarisse, L. and Coheur, P.-F. and Horowitz, L.W.},
  title = {Gas-aerosol partitioning of ammonia in biomass burning plumes: Implications for the interpretation of spaceborne observations of ammonia and the radiative forcing of ammonium nitrate},
  journal = {Geophysical Research Letters},
  year = {2017},
  volume = {44},
  pages = {8084-8093},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028422579&doi=10.1002%2f2017GL074215&partnerID=40&md5=0530d5130a263c9a7935bdc2f44f0b07},
  doi = {10.1002/2017GL074215}
}
Abstract: Formic acid (HCOOH) concentrations are often underestimated by models, and its chemistry is highly uncertain. HCOOH is, however, among the most abundant atmospheric volatile organic compounds, and it is potentially responsible for rain acidity in remote areas. HCOOH data from the Infrared Atmospheric Sounding Interferometer (IASI) are analyzed from 2008 to 2014 to estimate enhancement ratios from biomass burning emissions over seven regions. Fire-affected HCOOH and CO total columns are defined by combining total columns from IASI, geographic location of the fires from Moderate Resolution Imaging Spectroradiometer (MODIS), and the surface wind speed field from the European Centre for Medium-Range Weather Forecasts (ECMWF). Robust correlations are found between these fire-affected HCOOH and CO total columns over the selected biomass burning regions, allowing the calculation of enhancement ratios equal to 7.30g × g 10g'3g ±g 0.08g × g 10g'3g molg molg'1 over Amazonia (AMA), 11.10g × g 10g'3g ±g 1.37g × g 10g'3g molg molg'1 over Australia (AUS), 6.80g × g 10g'3g ±g 0.44g × g 10g'3g molg molg'1 over India (IND), 5.80g × g 10g'3g ±g 0.15g × g 10g'3g molg molg'1 over Southeast Asia (SEA), 4.00g × g 10g'3g ±g 0.19g × g 10g'3g molg molg'1 over northern Africa (NAF), 5.00g × g 10g'3g ±g 0.13g × g 10g'3g molg molg'1 over southern Africa (SAF), and 4.40g × g 10g'3g ±g 0.09g × g 10g'3g molg molg'1 over Siberia (SIB), in a fair agreement with previous studies. In comparison with referenced emission ratios, it is also shown that the selected agricultural burning plumes captured by IASI over India and Southeast Asia correspond to recent plumes where the chemistry or the sink does not occur. An additional classification of the enhancement ratios by type of fuel burned is also provided, showing a diverse origin of the plumes sampled by IASI, especially over Amazonia and Siberia. The variability in the enhancement ratios by biome over the different regions show that the levels of HCOOH and CO do not only depend on the fuel types. © Author(s) 2017.
BibTeX:
@article{PommierClerbauxCoheur2017,
  author = {Pommier, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {Determination of enhancement ratios of HCOOH relative to CO in biomass burning plumes by the Infrared Atmospheric Sounding Interferometer (IASI)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2017},
  volume = {17},
  pages = {11089-11105},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029716214&doi=10.5194%2facp-17-11089-2017&partnerID=40&md5=c7f029b4f9223b304538fbed73bf122a},
  doi = {10.5194/acp-17-11089-2017}
}
Abstract: Recent measurements over the Northern Hemisphere indicate that the long-term decline in the atmospheric burden of ethane (C2H6) has ended and the abundance increased dramatically between 2010 and 2014. The rise in C2H6 atmospheric abundances has been attributed to oil and natural gas extraction in North America. Existing global C2H6 emission inventories are based on outdated activity maps that do not account for current oil and natural gas exploitation regions. We present an updated global C2H6 emission inventory based on 2010 satellite-derived CH4 fluxes with adjusted C2H6 emissions over the U.S. from the National Emission Inventory (NEI 2011). We contrast our global 2010 C2H6 emission inventory with one developed for 2001. The C2H6 difference between global anthropogenic emissions is subtle (7.9 versus 7.2 Tg yr-1), but the spatial distribution of the emissions is distinct. In the 2010 C2H6 inventory, fossil fuel sources in the Northern Hemisphere represent half of global C2H6 emissions and 95% of global fossil fuel emissions. Over the U.S., unadjusted NEI 2011 C2H6 emissions produce mixing ratios that are 14-50% of those observed by aircraft observations (2008-2014). When the NEI 2011 C2H6 emission totals are scaled by a factor of 1.4, the Goddard Earth Observing System Chem model largely reproduces a regional suite of observations, with the exception of the central U.S., where it continues to underpredict observed mixing ratios in the lower troposphere. We estimate monthly mean contributions of fossil fuel C2H6 emissions to ozone and peroxyacetyl nitrate surface mixing ratios over North America of ~ 1% and ~8%, respectively. © 2017. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Tzompa-SosaMahieuFrancoEtAl2017,
  author = {Tzompa-Sosa, Z.A. and Mahieu, E. and Franco, B. and Keller, C.A. and Turner, A.J. and Helmig, D. and Fried, A. and Richter, D. and Weibring, P. and Walega, J. and Yacovitch, T.I. and Herndon, S.C. and Blake, D.R. and Hase, F. and Hannigan, J.W. and Conway, S. and Strong, K. and Schneider, M. and Fischer, E.V.},
  title = {Revisiting global fossil fuel and biofuel emissions of ethane},
  journal = {Journal of Geophysical Research},
  year = {2017},
  volume = {122},
  pages = {2493-2512},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014240899&doi=10.1002%2f2016JD025767&partnerID=40&md5=2c0469c30c7cf6f6629de664ceecd743},
  doi = {10.1002/2016JD025767}
}
Abstract: Recently, Whitburn et al.(2016) presented a neural-network-based algorithm for retrieving atmospheric ammonia (NH3) columns from Infrared Atmospheric Sounding Interferometer (IASI) satellite observations. In the past year, several improvements have been introduced, and the resulting new baseline version, Artificial Neural Network for IASI (ANNI)-NH3-v2.1, is documented here. One of the main changes to the algorithm is that separate neural networks were trained for land and sea observations, resulting in a better training performance for both groups. By reducing and transforming the input parameter space, performance is now also better for observations associated with favourable sounding conditions (i.e. enhanced thermal contrasts). Other changes relate to the introduction of a bias correction over land and sea and the treatment of the satellite zenith angle. In addition to these algorithmic changes, new recommendations for post-filtering the data and for averaging data in time or space are formulated. We also introduce a second dataset (ANNI-NH3-v2.1R-I) which relies on ERA-Interim ECMWF meteorological input data, along with surface temperature retrieved from a dedicated network, rather than the operationally provided Eumetsat IASI Level 2 (L2) data used for the standard near-real-time version. The need for such a dataset emerged after a series of sharp discontinuities were identified in the NH3 time series, which could be traced back to incremental changes in the IASI L2 algorithms for temperature and clouds. The reanalysed dataset is coherent in time and can therefore be used to study trends. Furthermore, both datasets agree reasonably well in the mean on recent data, after the date when the IASI meteorological L2 version 6 became operational (30 September 2014). © Author(s) 2017. This work is distributed under the Creative Commons Attribution 4.0 License.
BibTeX:
@article{VanDammeWhitburnClarisseEtAl2017,
  author = {Van Damme, M. and Whitburn, S. and Clarisse, L. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {Version 2 of the IASI NH3 neural network retrieval algorithm: Near-real-time and reanalysed datasets},
  journal = {Atmospheric Measurement Techniques},
  year = {2017},
  volume = {10},
  pages = {4905-4914},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031322973&doi=10.5194%2famt-10-4905-2017&partnerID=40&md5=72d27ec7471ced333e66dfdcbba15f1e},
  doi = {10.5194/amt-10-4905-2017}
}
Abstract: Global efforts to mitigate climate change have largely focused on reducing emissions of carbon dioxide (CO2), which is responsible for 55-60% of current anthropogenic radiative forcing on warming impact. Because of its long lifetime (~130 years [1]) in the atmosphere, long-lasting CO2 will remain the primary driver of long-term temperature rise even if new CO2 emissions dropped to zero. A "fast-action" climate mitigation strategies is therefore strongly needed to provide more sizeable short-term benefits than CO2 reductions by reducing emission of short-lived climate pollutants (SLCPs), having atmospheric lifetimes of less than 20 years [2], which would allow for short-term drops in atmospheric concentrations and hence slow climate change over the next several decades. Monitoring of climatically and environmentally active SLCPs is important not only for policy-based reporting, but also for basic process-based understanding of climate related processes in the atmosphere. In this talk, we will overview our recent progress in the developments and applications of laserbased optical instruments for the measurements of environmental and livestock emitted methane (CH4), as well as the measurement of black carbon (BC) absorption. The experimental detail, the preliminary measurement results, the corresponding data processing and analysis will be presented. © 2017 SPIE.
BibTeX:
@conference{WangChenShenEtAl2017,
  author = {Wang, G. and Chen, D. and Shen, F. and Yi, H. and Maamary, R. and Augustin, P. and Fourmentin, M. and Dewaele, D. and Cazier, F. and Hubert, P. and Deguine, A. and Petitprez, D. and Fertein, E. and Sigrist, M.W. and Chen, W.},
  title = {Monitoring of short-lived climate pollutants by laser absorption spectroscopy},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2017},
  volume = {10111},
  article number = {1011105},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85025143025&doi=10.1117%2f12.2250809&partnerID=40&md5=6f9e809b77bae75f2fb7825f6c9ba186},
  doi = {10.1117/12.2250809}
}
Abstract: A photoacoustic (PA) spectrophone was developed for filter-free measurement of black carbon (BC) mass absorption coefficient (MAC) in the spectral region of ∼ 442 nm using a blue diode laser. The PA sensor was characterized and calibrated using NO2 at standard calibrated concentrations, as well as at indoor and outdoor air concentrations via a side-by-side intercomparison with a commercial NOx analyzer. Black carbon (graphite) and volcanic ash samples were measured under laboratory condition. MAC of BC and volcanic ash sample were determined based on the measured particles optical absorption coefficient by the PA spectrophone, in combination with the mass concentration measured using a scanning mobility particle sizer (SMPS). A minimum detectable absorption coefficient (1σ) of ∼ 1.2 Mm-1 for BC was achieved with a time solution of 1 second. © 2017 SPIE.
BibTeX:
@conference{WangYiHubertEtAl2017,
  author = {Wang, G. and Yi, H. and Hubert, P. and Deguine, A. and Petitprez, D. and Maamary, R. and Fertein, E. and Rey, J.M. and Sigrist, M.W. and Chen, W.},
  title = {Filter-free measurements of black carbon absorption using photoacoustic spectroscopy},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2017},
  volume = {10111},
  article number = {1011136},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034448454&doi=10.1117%2f12.2251093&partnerID=40&md5=fb8ad360db98e8a48e6d8d1a9b15266b},
  doi = {10.1117/12.2251093}
}
Abstract: We analyze the ozone (O3) variability in the troposphere (from ground to 300 hPa) using 8 years (January 2008 to March 2016) of O3 profile measurements provided by the Infrared Atmospheric Sounding Interferometer (IASI) on board the MetOp satellite. The capability of IASI to monitor the year-to-year variability in that layer is examined first in terms of vertical sensitivity, a priori contribution, and correlations in the deseasonalized anomalies with the upper layers. We present global patterns of the main geophysical drivers (e.g., solar flux, Quasi-biennal Oscillation-QBO, North Atlantic Oscillation-NAO, and El Niño-Southern Oscillation-ENSO) of IASI O3 variations, obtained by applying appropriate annual and seasonal multivariate regression models on time series of spatially gridded averaged O3. The results show that the models are able to explain most of the O3 variability captured by IASI. Large O3 changes in the North Arctic/Euro-Atlantic sector and over the equatorial band are attributed to the NAO and the QBO effects, respectively. ENSO is modeled as the main contributor to the O3 variations in the tropical band where direct effects of warm and cool ENSO phases are highlighted with a clear tropical-extratropical gradient. A strong west-east gradient in the tropics is also found and likely reflects an indirect effect related to ENSO dry conditions. Finally, we also show that the ENSO perturbs the O3 variability far from the tropics into middle and high latitudes where a significant 4-month time-lag in the response of O3 to ENSO is identified for the first time. © 2017. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{WespesHurtmansClerbauxEtAl2017,
  author = {Wespes, C. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {O3 variability in the troposphere as observed by IASI over 2008-2016: Contribution of atmospheric chemistry and dynamics},
  journal = {Journal of Geophysical Research},
  year = {2017},
  volume = {122},
  pages = {2429-2451},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013499616&doi=10.1002%2f2016JD025875&partnerID=40&md5=35b9517f7d942df92ddb7f2f3a206219},
  doi = {10.1002/2016JD025875}
}
Abstract: Vegetation fires are a major source of ammonia (NH3) in the atmosphere. Their emissions are mainly estimated using bottom-up approaches that rely on uncertain emission factors. In this study, we derive new biome-specific NH3 enhancement ratios relative to carbon monoxide (CO), ERNH3 / CO (directly related to the emission factors), from the measurements of the IASI sounder onboard the Metop-A satellite. This is achieved for large tropical regions and for an 8-year period (2008-2015). We find substantial differences in the ERNH3 / CO ratios between the biomes studied, with calculated values ranging from 7 × 10-3 to 23 × 10-3. For evergreen broadleaf forest these are typically 50-75% higher than for woody savanna and savanna biomes. This variability is attributed to differences in fuel types and size and is in line with previous studies. The analysis of the spatial and temporal distribution of the ERNH3 / CO ratio also reveals a (sometimes large) within-biome variability. On a regional level, woody savanna shows, for example, a mean ERNH3 / CO ratio for the region of Africa south of the Equator that is 40-75% lower than in the other five regions studied, probably reflecting regional differences in fuel type and burning conditions. The same variability is also observed on a yearly basis, with a peak in the ERNH3 / CO ratio observed for the year 2010 for all biomes. These results highlight the need for the development of dynamic emission factors that take into better account local variations in fuel type and fire conditions. We also compare the IASI-derived ERNH3 / CO ratio with values reported in the literature, usually calculated from ground-based or airborne measurements. We find general good agreement in the referenced ERNH3 / CO ratio except for cropland, for which the ERNH3 / CO ratio shows an underestimation of about 2-2.5 times. © 2017 Author(s).
BibTeX:
@article{WhitburnVanDammeClarisseEtAl2017,
  author = {Whitburn, S. and Van Damme, M. and Clarisse, L. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {IASI-derived NH3 enhancement ratios relative to CO for the tropical biomass burning regions},
  journal = {Atmospheric Chemistry and Physics},
  year = {2017},
  volume = {17},
  pages = {12239-12252},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031316360&doi=10.5194%2facp-17-12239-2017&partnerID=40&md5=026799880826fac59cb5cb94054508e5},
  doi = {10.5194/acp-17-12239-2017}
}
Abstract: China is a global hotspot of atmospheric ammonia (NH3) emissions and, as a consequence, very high nitrogen (N) deposition levels are documented. However, previous estimates of total NH3 emissions in China were much lower than inference from observed deposition values would suggest, highlighting the need for further investigation. Here, we reevaluated NH3 emissions based on a mass balance approach, validated by N deposition monitoring and satellite observations, for China for the period of 2000 to 2015. Total NH3 emissions in China increased from 12.1 ± 0.8 Tg N yr-1 in 2000 to 15.6 ± 0.9 Tg N yr-1 in 2015 at an annual rate of 1.9%, which is approximately 40% higher than existing studies suggested. This difference is mainly due to more emission sources now having been included and NH3 emission rates from mineral fertilizer application and livestock having been underestimated previously. Our estimated NH3 emission levels are consistent with the measured deposition of NHx (including NH4 + and NH3) on land (11-14 Tg N yr-1) and the substantial increases in NH3 concentrations observed by satellite measurements over China. These findings substantially improve our understanding on NH3 emissions, implying that future air pollution control strategies have to consider the potentials of reducing NH3 emission in China. © 2017 American Chemical Society.
BibTeX:
@article{ZhangWuLiuEtAl2017,
  author = {Zhang, X. and Wu, Y. and Liu, X. and Reis, S. and Jin, J. and Dragosits, U. and Van Damme, M. and Clarisse, L. and Whitburn, S. and Coheur, P.-F. and Gu, B.},
  title = {Ammonia emissions may be substantially underestimated in China},
  journal = {Environmental Science and Technology},
  year = {2017},
  volume = {51},
  pages = {12089-12096},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040041721&doi=10.1021%2facs.est.7b02171&partnerID=40&md5=c80187d679699343d7f51f76517f23d1},
  doi = {10.1021/acs.est.7b02171}
}
Abstract: The vulnerability of the European airspace to volcanic eruptions was brought to the attention of the public and the scientific community by the 2010 eruptions of the Icelandic volcano Eyjafjallajökull. As a consequence of this event, ash concentration thresholds replaced the ĝ zero tolerance to ashĝ€ rule, drastically changing the requirements on satellite ash retrievals. In response to that, the ESA funded several projects aiming at creating an optimal end-to-end system for volcanic ash plume monitoring and prediction. Two of them, namely the SACS-2 and SMASH projects, developed and improved dedicated satellite-derived ash plume and sulfur dioxide level assessments. The validation of volcanic ash levels and height extracted from the GOME-2 and IASI instruments on board the MetOp-A satellite is presented in this work. EARLINET lidar measurements are compared to different satellite retrievals for two eruptive episodes in April and May 2010. Comparisons were also made between satellite retrievals and aircraft lidar data obtained with the UK's BAe-146-301 Atmospheric Research Aircraft (managed by the Facility for Airborne Atmospheric Measurements, FAAM) over the United Kingdom and the surrounding regions. The validation results are promising for most satellite products and are within the estimated uncertainties of each of the comparative data sets, but more collocation scenes would be desirable to perform a comprehensive statistical analysis. The satellite estimates and the validation data sets are better correlated for high ash optical depth values, with correlation coefficients greater than 0.8. The IASI retrievals show a better agreement concerning the ash optical depth and ash layer height when compared with the ground-based and airborne lidar data. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX:
@article{BalisKoukouliSiomosEtAl2016,
  author = {Balis, D. and Koukouli, M.-E. and Siomos, N. and Dimopoulos, S. and Mona, L. and Pappalardo, G. and Marenco, F. and Clarisse, L. and J Ventress, L. and Carboni, E. and G Grainger, R. and Wang, P. and Tilstra, G. and Van Der A, R. and Theys, N. and Zehner, C.},
  title = {Validation of ash optical depth and layer height retrieved from passive satellite sensors using EARLINET and airborne lidar data: the case of the Eyjafjallajökull eruption},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {5705-5720},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84969752471&doi=10.5194%2facp-16-5705-2016&partnerID=40&md5=f57c8c3bff6a32b76be8d0c545c58f67},
  doi = {10.5194/acp-16-5705-2016}
}
Abstract: The 2010 eruptions of the Icelandic volcano Eyjafjallajokull attracted the attention of the public and the scientific community to the vulnerability of the European airspace to volcanic eruptions. The European Space Agency project "Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards", called for the creation of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction. This system is based on improved and dedicated satellite-derived ash plume and sulphur dioxide level assessments, as well as an extensive validation, using among others ground-based measurements (Koukouli et al., 2014). The validation of volcanic ash levels and height extracted from IASI/MetopA is presented in this work with emphasis on the ash plume height and ash optical depth levels. European Aerosol Research Lidar Network [EARLINET] lidar measurements are compared to different satellite estimates for two eruptive episodes. The validation results are extremely promising within the estimated uncertainties of each of the comparative datasets. © 2016 Owned by the authors, published by EDP Sciences.
BibTeX:
@conference{BalisSiomosKoukouliEtAl2016,
  author = {Balis, D. and Siomos, N. and Koukouli, M. and Clarisse, L. and Carboni, E. and Ventress, L. and Grainger, R. and Mona, L. and Pappalardo, G.},
  title = {Validation of ASH Optical Depth and Layer Height from IASI using Earlinet Lidar Data},
  journal = {EPJ Web of Conferences},
  year = {2016},
  volume = {119},
  article number = {07006},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976291236&doi=10.1051%2fepjconf%2f201611907006&partnerID=40&md5=5df4b8f23c15b09b99d54cc436f5e0f3},
  doi = {10.1051/epjconf/201611907006}
}
Abstract: SO2 from volcanic eruptions is now operationally monitored from space in both the ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO2 has almost solely been measured from UV sounders. Indeed, TIR instruments are well known to have a poor sensitivity to the planetary boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability of the Infrared Atmospheric Sounding Interferometer (IASI) to measure near-surface SO2 locally, for specific atmospheric conditions. In this work, we develop a retrieval method allowing the inference of SO2 near-surface concentrations from IASI measurements at a global scale. This method consists of two steps. Both are based on the computation of radiance indexes representing the strength of the SO2 ν3 band in IASI spectra. The first step allows the peak altitude of SO2 to be retrieved and near-surface SO2 to be selected. In the second step, 0-4 km columns of SO2 are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface SO2 from IASI-A, and identify the dominant anthropogenic hotspot sources and volcanic degassing. The 7-year daily time evolution of SO2 columns above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran) is investigated and correlated to the seasonal variations of the parameters that drive the IASI sensitivity to the PBL composition. Apart from TC, we show that humidity is the most important parameter which determines IR sensitivity to nearsurface SO2 in the ν3 band. As IASI provides global measurements twice daily, the differences between the retrieved columns for the morning and evening orbits are investigated. This paper finally presents a first intercomparison of the measured 0-4 km columns with an independent iterative retrieval method and with observations of the Ozone Monitoring Instrument (OMI). © Author(s) 2016.
BibTeX:
@article{BauduinClarisseHadji-LazaroEtAl2016,
  author = {Bauduin, S. and Clarisse, L. and Hadji-Lazaro, J. and Theys, N. and Clerbaux, C. and Coheur, P.-F.},
  title = {Retrieval of near-surface sulfur dioxide (SO2) concentrations at a global scale using IASI satellite observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {721-740},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959314884&doi=10.5194%2famt-9-721-2016&partnerID=40&md5=8317bb6b941f8bacc74f77911324cbd7},
  doi = {10.5194/amt-9-721-2016}
}
Abstract: The 2014-2015 Holuhraun lava-flood eruption of Bároarbunga volcano (Iceland) emitted prodigious amounts of sulfur dioxide into the atmosphere. This eruption caused a large-scale episode of air pollution throughout Western Europe in September 2014, the first event of this magnitude recorded in the modern era. We gathered chemistry-transport simulations and a wealth of complementary observations from satellite sensors (OMI, IASI), ground-based remote sensing (lidar, sunphotometry, differential optical absorption spectroscopy) and ground-level air quality monitoring networks to characterize both the spatial-temporal distributions of volcanic SO2 and sulfate aerosols as well as the dynamics of the planetary boundary layer. Time variations of dynamical and microphysical properties of sulfate aerosols in the aged low-tropospheric volcanic cloud, including loading, vertical distribution, size distribution and single scattering albedo, are provided. Retrospective chemistry-transport simulations at low horizontal resolution (25 km × 25 km) capture the correct temporal dynamics of this far-range air pollution event but fail to reproduce the correct magnitude of SO2 concentration at ground-level. Simulations at higher spatial resolution, relying on two nested domains with finest resolution of 7.3 km × 7.3 km, improve substantially the far-range vertical distribution of the volcanic cloud and subsequently the description of ground-level SO2 concentrations. However, remaining discrepancies between model and observations are shown to result from an inaccurate representation of the planetary boundary layer (PBL) dynamics. Comparison with lidar observations points out a systematic under-estimation of the PBL height by the model, whichever the PBL parameterization scheme. Such a shortcoming impedes the capture of the overlying Bároarbunga cloud into the PBL at the right time and in sufficient quantities. This study therefore demonstrates the key role played by the PBL dynamics in accurately modelling large-scale volcanogenic air pollution. © 2016 Author(s).
BibTeX:
@article{BoichuChiapelloBrogniezEtAl2016,
  author = {Boichu, M. and Chiapello, I. and Brogniez, C. and Péré, J.-C. and Thieuleux, F. and Torres, B. and Blarel, L. and Mortier, A. and Podvin, T. and Goloub, P. and Söhne, N. and Clarisse, L. and Bauduin, S. and Hendrick, F. and Theys, N. and Van Roozendael, M. and Tanré, D.},
  title = {Current challenges in modelling far-range air pollution induced by the 2014-2015 Bároarbunga fissure eruption (Iceland)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10831-10845},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84986309965&doi=10.5194%2facp-16-10831-2016&partnerID=40&md5=49d9cdf3f3c89cd98480e76447145150},
  doi = {10.5194/acp-16-10831-2016}
}
Abstract: This paper presents an extensive intercomparison and validation for the ozone (O3) product measured by the two Infrared Atmospheric Sounding Interferometers (IASIs) launched on board the MetOp-A and MetOp-B satellites in 2006 and in 2012 respectively. IASI O3 total columns and vertical profiles obtained from Fast Optimal Retrievals on Layers for IASI (FORLI) v20140922 software (running up until recently) are validated against independent observations during the period 2008-2014 on a global scale. On average for the period 2013-2014, IASI-A and IASI-B total ozone columns (TOCs) retrieved using FORLI are consistent, with IASI-B providing slightly lower values with a global difference of only 0.2±0.8%. The comparison between IASI-A and IASI-B O3 vertical profiles shows differences within ±2% over the entire altitude range. Global validation results for 7 years of IASI TOCs from FORLI against the Global Ozone Monitoring Experiment-2 (GOME-2) launched on board MetOp-A and Brewer-Dobson data show that, on average, IASI overestimates the ultraviolet (UV) data by 5-6% with the largest differences found in the southern high latitudes. The comparison with UV-visible SAOZ (Système d'Analyse par Observation Zénithale) measurements shows a mean bias between IASI and SAOZ TOCs of 2-4% in the midlatitudes and tropics and 7% at the polar circle. Part of the discrepancies found at high latitudes can be attributed to the limited information content in the observations due to low brightness temperatures. The comparison with ozonesonde vertical profiles (limited to 30km) shows that on average IASI with FORLI processing underestimates O3 by ∼ 5-15% in the troposphere while it overestimates O3 by ∼ 10-40% in the stratosphere, depending on the latitude. The largest relative differences are found in the tropical tropopause region; this can be explained by the low O3 amounts leading to large relative errors. In this study, we also evaluate an updated version of FORLI-O3 retrieval software (v20151001), using look-up tables recalculated to cover a larger spectral range using the latest HITRAN spectroscopic database (HITRAN 2012) and implementing numerical corrections. The assessment of the new O3 product with the same set of observations as that used for the validation exercise shows a correction of ∼ 4% for the TOC positive bias when compared to the UV ground-based and satellite observations, bringing the overall global comparison to ∼ 1-2% on average. This improvement is mainly associated with a decrease in the retrieved O3 concentration in the middle stratosphere (above 30hPa/25km) as shown by the comparison with ozonesonde data. © Author(s) 2016.
BibTeX:
@article{BoynardHurtmansKoukouliEtAl2016,
  author = {Boynard, A. and Hurtmans, D. and Koukouli, M.E. and Goutail, F. and Bureau, J. and Safieddine, S. and Lerot, C. and Hadji-Lazaro, J. and Wespes, C. and Pommereau, J.-P. and Pazmino, A. and Zyrichidou, I. and Balis, D. and Barbe, A. and Mikhailenko, S.N. and Loyola, D. and Valks, P. and Van Roozendael, M. and Coheur, P.-F. and Clerbaux, C.},
  title = {Seven years of IASI ozone retrievals from FORLI: Validation with independent total column and vertical profile measurements},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {4327-4353},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84986266353&doi=10.5194%2famt-9-4327-2016&partnerID=40&md5=0402be57aa6d71a6cab2ad9f3d4b247b},
  doi = {10.5194/amt-9-4327-2016}
}
Abstract: Satellite instruments have been providing measurements of global volcanic emissions of sulfur dioxide (SO2) since 1978, based on observations in the ultraviolet (UV), infrared (IR) and microwave spectral bands. We review recent advances in satellite remote sensing of volcanic gases, focusing on increased instrument sensitivity to tropospheric SO2 emissions and techniques to determine volcanic plume altitude. A synthesis of ~36 years of global UV, IR and microwave satellite measurements yields an updated assessment of the volcanic SO2 flux to the upper troposphere and lower stratosphere (UTLS) between 1978 and 2014 (~1-Tg/yr). The present availability of multiple UV and IR satellite SO2 products provides increased confidence in calculated SO2 loadings for many eruptions. We examine the temporal and latitudinal distribution of volcanic SO2 emissions and reassess the relationship between eruptive SO2 discharge and eruption magnitude, finding a first-order correlation between SO2 emission and volcanic explosivity index (VEI), but with significant scatter. Based on the observed SO2-VEI relation, we estimate the fraction of eruptive SO2 emissions released by the smallest eruptions (~0.48 Tg/yr), which is not recorded by satellite observations. A detailed breakdown of the sources of measured SO2 emissions reveals intuitively expected correlations between eruption frequency, SO2 loading and volcanic degassing style. We discuss new constraints on e-folding times for SO2 removal in volcanic plumes, and highlight recent measurements of volcanic hydrogen chloride (HCl) injections into the UTLS. An analysis of passive volcanic emissions of SO2 detected in Ozone Monitoring Instrument (OMI) SO2 data since 2004 provides new insight into the location and stability of the dominant sources of volcanic SO2 over the past decade. Since volcanic SO2 emissions constitute a random, highly variable perturbation to the atmosphere-climate system, continued monitoring of volcanic SO2 emissions from space by multiple UV and IR instruments to extend the current multi-decadal record is essential, and near-global, geostationary measurements of SO2 may be available by the end of the current decade. © 2016 The Authors.
BibTeX:
@article{CarnClarissePrata2016,
  author = {Carn, S.A. and Clarisse, L. and Prata, A.J.},
  title = {Multi-decadal satellite measurements of global volcanic degassing},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2016},
  volume = {311},
  pages = {99-134},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957928444&doi=10.1016%2fj.jvolgeores.2016.01.002&partnerID=40&md5=26fb206259c2631f22af50cd18478d26},
  doi = {10.1016/j.jvolgeores.2016.01.002}
}
Abstract: In the first part of this chapter, the spectral content of the thermal infrared spectral region for the sounding of volcanic eruptions is explored through analysis of simulated and real observed spectra. Next, we review the literature on algorithms for the identification and retrieval of volcanic ash, both from broadband and hyperspectral infrared measurements. The final part of this chapter treats the topic of validation of satellite-based ash retrievals. © 2016 Elsevier Ltd. All rights reserved.
BibTeX:
@book{ClarissePrata2016,
  author = {Clarisse, L. and Prata, F.},
  title = {Infrared Sounding of Volcanic Ash},
  journal = {Volcanic Ash: Hazard Observation},
  year = {2016},
  pages = {189-215},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009675469&doi=10.1016%2fB978-0-08-100405-0.00017-3&partnerID=40&md5=f9815abb81f4729884302853d02f4098},
  doi = {10.1016/B978-0-08-100405-0.00017-3}
}
Abstract: Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (<i>N</i>obs Combining double low line 547) give a mean relative difference of ĝ'32.4ĝ€±ĝ€(56.3)ĝ€%, a correlation <i>r</i> of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (-50 to +100%). © Author(s) 2016.
BibTeX:
@article{DammersPalmVanDammeEtAl2016,
  author = {Dammers, E. and Palm, M. and Van Damme, M. and Vigouroux, C. and Smale, D. and Conway, S. and Toon, G.C. and Jones, N. and Nussbaumer, E. and Warneke, T. and Petri, C. and Clarisse, L. and Clerbaux, C. and Hermans, C. and Lutsch, E. and Strong, K. and Hannigan, J.W. and Nakajima, H. and Morino, I. and Herrera, B. and Stremme, W. and Grutter, M. and Schaap, M. and Kruit, R.J.W. and Notholt, J. and Coheur, P.-F. and Erisman, J.W.},
  title = {An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10351-10368},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983238976&doi=10.5194%2facp-16-10351-2016&partnerID=40&md5=db100e43da9813172c113dc7e88e526d},
  doi = {10.5194/acp-16-10351-2016}
}
Abstract: Ammonia (NH3), whose main source in the troposphere is agriculture, is an important gaseous precursor of atmospheric particulate matter (PM). We derived daily ammonia emissions using NH3 total columns measured from the Infrared Atmospheric Sounding Interferometer (IASI) on board Metop-A, at a relatively high spatial resolution (grid cell of 0.5° × 0.5°). During the European spring haze episodes of 24–31 March 2012 and 8–15 March 2014, IASI reveals NH3 total column magnitudes highlighting higher NH3 emissions over central Europe (especially over Germany, Czech Republic, and eastern France) from the ones provided by the European reference European Monitoring and Evaluation Programme inventory. These ammonia emissions exhibit in addition a large day-to-day variability, certainly due to spreading practices. The increase of NH3 emissions in the model, that reaches +300% locally, leads to an increase of both NH3 and PM2.5 surface concentrations and allows for a better comparison with independent measurements (in terms of bias, root-mean-square error, and correlation). This study suggests that there are good prospects for better quantifying NH3 emissions by atmospheric inversions. ©2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Fortems-CheineyDufourHamaoui-LaguelEtAl2016,
  author = {Fortems-Cheiney, A. and Dufour, G. and Hamaoui-Laguel, L. and Foret, G. and Siour, G. and Van Damme, M. and Meleux, F. and Coheur, P.-F. and Clerbaux, C. and Clarisse, L. and Favez, O. and Wallasch, M. and Beekmann, M.},
  title = {Unaccounted variability in NH3 agricultural sources detected by IASI contributing to European spring haze episode},
  journal = {Geophysical Research Letters},
  year = {2016},
  volume = {43},
  pages = {5475-5482},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971301566&doi=10.1002%2f2016GL069361&partnerID=40&md5=d14e1dab17126135a250b8c6838d7ded},
  doi = {10.1002/2016GL069361}
}
Abstract: Only very few long-term records of formaldehyde (HCHO) exist that are suitable for trend analysis. Furthermore, many uncertainties remain as to its diurnal cycle, representing a large short-term variability superimposed on seasonal and inter-annual variations that should be accounted for when comparing ground-based observations to, e.g., model results. In this study, we derive a multi-decadal time series (January 1988-June 2015) of HCHO total columns from ground-based high-resolution Fourier transform infrared (FTIR) solar spectra recorded at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580ma. s. l. ), allowing for the characterization of the mid-latitudinal atmosphere for background conditions. First we investigate the HCHO diurnal variation, peaking around noontime and mainly driven by the intra-day insolation modulation and methane (CH4) oxidation. We also characterize quantitatively the diurnal cycles by adjusting a parametric model to the observations, which links the daytime to the HCHO columns according to the monthly intra-day regimes. It is then employed to scale all the individual FTIR measurements on a given daytime in order to remove the effect of the intra-day modulation for improving the trend determination and the comparison with HCHO columns simulated by the state-of-the-art GEOS-Chem v9-02 chemical transport model. Such a parametric model will be useful to scale the Jungfraujoch HCHO columns on satellite overpass times in the framework of future calibration/validation efforts of space-borne sensors. GEOS-Chem sensitivity tests suggest then that the seasonal and inter-annual HCHO column variations above Jungfraujoch are predominantly led by the atmospheric CH4 oxidation, with a maximum contribution of 25% from the anthropogenic non-methane volatile organic compound precursors during wintertime. Finally, trend analysis of the so-scaled 27-year FTIR time series reveals a long-term evolution of the HCHO columns in the remote troposphere to be related to the atmospheric CH4 fluctuations and the short-term OH variability: +2.9%year-1 between 1988 and 1995, -3.7%year-1 over 1996-2002 and +0.8%year-1 from 2003 onwards. © Author(s) 2016.
BibTeX:
@article{FrancoAMaraisBovyEtAl2016,
  author = {Franco, B. and A Marais, E. and Bovy, B. and Bader, W. and Lejeune, B. and Roland, G. and Servais, C. and Mahieu, E.},
  title = {Diurnal cycle and multi-decadal trend of formaldehyde in the remote atmosphere near 46°N},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {4171-4189},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84963819332&doi=10.5194%2facp-16-4171-2016&partnerID=40&md5=770ed5b42a53320e90a6bf65acef9a4c},
  doi = {10.5194/acp-16-4171-2016}
}
Abstract: Sharp rises in the atmospheric abundance of ethane (C2H6) have been detected from 2009 onwards in the Northern Hemisphere as a result of the unprecedented growth in the exploitation of shale gas and tight oil reservoirs in North America. Using time series of C2H6 total columns derived from ground-based Fourier transform infrared (FTIR) observations made at five selected Network for the Detection of Atmospheric Composition Change sites, we characterize the recent C2H6 evolution and determine growth rates of ∼5% yr-1 at mid-latitudes and of ∼3% yr-1 at remote sites. Results from CAM-chem simulations with the Hemispheric Transport of Air Pollutants, Phase II bottom-up inventory for anthropogenic emissions are found to greatly underestimate the current C2H6 abundances. Doubling global emissions is required to reconcile the simulations and the observations prior to 2009. We further estimate that North American anthropogenic C2H6 emissions have increased from 1.6 Tg yr-1 in 2008 to 2.8 Tg yr-1 in 2014, i.e. by 75% over these six years. We also completed a second simulation with new top-down emissions of C2H6 from North American oil and gas activities, biofuel consumption and biomass burning, inferred from space-borne observations of methane (CH4) from Greenhouse Gases Observing SATellite. In this simulation, GEOS-Chem is able to reproduce FTIR measurements at the mid-latitudinal sites, underscoring the impact of the North American oil and gas development on the current C2H6 abundance. Finally we estimate that the North American oil and gas emissions of CH4, a major greenhouse gas, grew from 20 to 35 Tg yr-1 over the period 2008-2014, in association with the recent C2H6 rise. © 2016 IOP Publishing Ltd.
BibTeX:
@article{FrancoMahieuEmmonsEtAl2016,
  author = {Franco, B. and Mahieu, E. and Emmons, L.K. and Tzompa-Sosa, Z.A. and Fischer, E.V. and Sudo, K. and Bovy, B. and Conway, S. and Griffin, D. and Hannigan, J.W. and Strong, K. and Walker, K.A.},
  title = {Evaluating ethane and methane emissions associated with the development of oil and natural gas extraction in North America},
  journal = {Environmental Research Letters},
  year = {2016},
  volume = {11},
  article number = {044010},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964770435&doi=10.1088%2f1748-9326%2f11%2f4%2f044010&partnerID=40&md5=3ca6c27af555723b1cb1fe97499a036a},
  doi = {10.1088/1748-9326/11/4/044010}
}
Abstract: Non-methane hydrocarbons such as ethane are important precursors to tropospheric ozone and aerosols. Using data from a global surface network and atmospheric column observations we show that the steady decline in the ethane mole fraction that began in the 1970s halted between 2005 and 2010 in most of the Northern Hemisphere and has since reversed. We calculate a yearly increase in ethane emissions in the Northern Hemisphere of 0.42 (±0.19) Tg yr-1 between mid-2009 and mid-2014. The largest increases in ethane and the shorter-lived propane are seen over the central and eastern USA, with a spatial distribution that suggests North American oil and natural gas development as the primary source of increasing emissions. By including other co-emitted oil and natural gas non-methane hydrocarbons, we estimate a Northern Hemisphere total non-methane hydrocarbon yearly emission increase of 1.2 (±0.8) Tg yr-1. Atmospheric chemical transport modelling suggests that these emissions could augment summertime mean surface ozone by several nanomoles per mole near oil and natural gas production regions. Methane/ethane oil and natural gas emission ratios could suggest a significant increase in associated methane emissions; however, this increase is inconsistent with observed leak rates in production regions and changes in methane's global isotopic ratio. © 2016 Macmillan Publishers Limited.
BibTeX:
@article{HelmigRossabiHueberEtAl2016,
  author = {Helmig, D. and Rossabi, S. and Hueber, J. and Tans, P. and Montzka, S.A. and Masarie, K. and Thoning, K. and Plass-Duelmer, C. and Claude, A. and Carpenter, L.J. and Lewis, A.C. and Punjabi, S. and Reimann, S. and Vollmer, M.K. and Steinbrecher, R. and Hannigan, J.W. and Emmons, L.K. and Mahieu, E. and Franco, B. and Smale, D. and Pozzer, A.},
  title = {Reversal of global atmospheric ethane and propane trends largely due to US oil and natural gas production},
  journal = {Nature Geoscience},
  year = {2016},
  volume = {9},
  pages = {490-495},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976889217&doi=10.1038%2fngeo2721&partnerID=40&md5=250792f191eb336070e695a3ad0e5061},
  doi = {10.1038/ngeo2721}
}
Abstract: Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in stratospheric aerosol research since the last comprehensive assessment of stratospheric aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of stratospheric aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term stratospheric aerosol climatology. Currently, changes in stratospheric aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of stratospheric sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that stratospheric aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes. ©2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{KremserThomasonHobeEtAl2016,
  author = {Kremser, S. and Thomason, L.W. and von Hobe, M. and Hermann, M. and Deshler, T. and Timmreck, C. and Toohey, M. and Stenke, A. and Schwarz, J.P. and Weigel, R. and Fueglistaler, S. and Prata, F.J. and Vernier, J.-P. and Schlager, H. and Barnes, J.E. and Antuña-Marrero, J.-C. and Fairlie, D. and Palm, M. and Mahieu, E. and Notholt, J. and Rex, M. and Bingen, C. and Vanhellemont, F. and Bourassa, A. and Plane, J.M.C. and Klocke, D. and Carn, S.A. and Clarisse, L. and Trickl, T. and Neely, R. and James, A.D. and Rieger, L. and Wilson, J.C. and Meland, B.},
  title = {Stratospheric aerosol—Observations, processes, and impact on climate},
  journal = {Reviews of Geophysics},
  year = {2016},
  volume = {54},
  pages = {278-335},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84966359545&doi=10.1002%2f2015RG000511&partnerID=40&md5=f3dcf89a3c96777a7d4659170fc11397},
  doi = {10.1002/2015RG000511}
}
Abstract: Formic acid (HCOOH) is one of the most abundant volatile organic compounds in the atmosphere. It is a major contributor to rain acidity in remote areas. There are, however, large uncertainties on the sources and sinks of HCOOH and therefore HCOOH is misrepresented by global chemistry-transport models. This work presents global distributions from 2008 to 2014 as derived from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI), based on conversion factors between brightness temperature differences and representative retrieved total columns over seven regions: Northern Africa, southern Africa, Amazonia, Atlantic, Australia, Pacific, and Russia. The dependence of the measured HCOOH signal on the thermal contrast is taken into account in the conversion method. This conversion presents errors lower than 20% for total columns ranging between 0.5 and 1×1016 molec cm-2 but reaches higher values, up to 78 %, for columns that are lower than 0:3×1016 molec cm-2. Signatures from biomass burning events are highlighted, such as in the Southern Hemisphere and in Russia, as well as biogenic emission sources, e.g., over the eastern USA. A comparison between 2008 and 2014 with ground-based Fourier transform infrared spectroscopy (FTIR) measurements obtained at four locations (Maido and Saint-Denis at La Réunion, Jungfraujoch, and Wollongong) is shown. Although IASI columns are found to correlate well with FTIR data, a large bias (> 100 %) is found over the two sites at La Réunion. A better agreement is found at Wollongong with a negligible bias. The comparison also highlights the difficulty of retrieving total columns from IASI measurements over mountainous regions such as Jungfraujoch. A comparison of the retrieved columns with the global chemistry-transport model IMAGESv2 is also presented, showing good representation of the seasonal and interannual cycles over America, Australia, Asia, and Siberia. A global model underestimation of the distribution and a misrepresentation of the seasonal cycle over India are also found. A small positive trend in the IASI columns is observed over Australia, Amazonia, and India over the 2008-2014 period (from 0.7 to 1.5%year-1), while a decrease of ∼0.8% year-1 is measured over Siberia. © Author(s) 2016.
BibTeX:
@article{PommierClerbauxCoheurEtAl2016,
  author = {Pommier, M. and Clerbaux, C. and Coheur, P.-F. and Mahieu, E. and Müller, J.-F. and Paton-Walsh, C. and Stavrakou, T. and Vigouroux, C.},
  title = {HCOOH distributions from IASI for 2008-2014: Comparison with ground-based FTIR measurements and a global chemistry-transport model},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {8963-8981},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84979596922&doi=10.5194%2facp-16-8963-2016&partnerID=40&md5=341021fe6dd08d714aeadfa90eefc947},
  doi = {10.5194/acp-16-8963-2016}
}
Abstract: Producing a global and comprehensive description of atmospheric aerosols requires integration of ground-based, airborne, satellite and model datasets. Due to its complexity, aerosol monitoring requires the use of several data records with complementary information content. This paper describes the lessons learned while developing and qualifying algorithms to generate aerosol Climate Data Records (CDR) within the European Space Agency (ESA) Aerosol_cci project. An iterative algorithm development and evaluation cycle involving core users is applied. It begins with the application-specific refinement of user requirements, leading to algorithm development, dataset processing and independent validation followed by user evaluation. This cycle is demonstrated for a CDR of total Aerosol Optical Depth (AOD) from two subsequent dual-view radiometers. Specific aspects of its applicability to other aerosol algorithms are illustrated with four complementary aerosol datasets. An important element in the development of aerosol CDRs is the inclusion of several algorithms evaluating the same data to benefit from various solutions to the ill-determined retrieval problem. The iterative approach has produced a 17-year AOD CDR, a 10-year stratospheric extinction profile CDR and a 35-year Absorbing Aerosol Index record. Further evolution cycles have been initiated for complementary datasets to provide insight into aerosol properties (i.e., dust aerosol, aerosol absorption). © 2016 by the authors.
BibTeX:
@article{PoppDeLeeuwBingenEtAl2016,
  author = {Popp, T. and De Leeuw, G. and Bingen, C. and Brühl, C. and Capelle, V. and Chedin, A. and Clarisse, L. and Dubovik, O. and Grainger, R. and Griesfeller, J. and Heckel, A. and Kinne, S. and Klüser, L. and Kosmale, M. and Kolmonen, P. and Lelli, L. and Litvinov, P. and Mei, L. and North, P. and Pinnock, S. and Povey, A. and Robert, C. and Schulz, M. and Sogacheva, L. and Stebel, K. and Zweers, D.S. and Thomas, G. and Tilstra, L.G. and Vandenbussche, S. and Veefkind, P. and Vountas, M. and Xue, Y.},
  title = {Development, production and evaluation of aerosol climate data records from European satellite observations (Aerosol_cci)},
  journal = {Remote Sensing},
  year = {2016},
  volume = {8},
  article number = {421},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971442640&doi=10.3390%2frs8050421&partnerID=40&md5=20ba1ec79eb892ee42359b01ae1c3399},
  doi = {10.3390/rs8050421}
}
BibTeX:
@article{Predoi-CrossUnniLiuEtAl2016,
  author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.},
  title = {Corrigendum to "Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing, and speed dependence" [J. Mol. Spectrosc. 245 (2007) 34-51]},
  journal = {Journal of Molecular Spectroscopy},
  year = {2016},
  volume = {322},
  pages = {55},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955570141&doi=10.1016%2fj.jms.2015.11.005&partnerID=40&md5=e0b8a529e809ce39fb45daeb2d98b562},
  doi = {10.1016/j.jms.2015.11.005}
}
Abstract: The ability of seven state-of-the-art chemistry-aerosol models to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over eastern Asia in summer 2008, is evaluated. The study focuses on the performance of models used to assess impacts of pollutants on climate and air quality as part of the EU ECLIPSE project. Models, run using the same ECLIPSE emissions, are compared over different spatial scales to in situ surface, vertical profiles and satellite data. Several rather clear biases are found between model results and observations, including overestimation of ozone at rural locations downwind of the main emission regions in China, as well as downwind over the Pacific. Several models produce too much ozone over polluted regions, which is then transported downwind. Analysis points to different factors related to the ability of models to simulate VOC-limited regimes over polluted regions and NOx limited regimes downwind. This may also be linked to biases compared to satellite NO2, indicating overestimation of NO2 over and to the north of the northern China Plain emission region. On the other hand, model NO2 is too low to the south and west of this region and over South Korea/Japan. Overestimation of ozone is linked to systematic underestimation of CO particularly at rural sites and downwind of the main Chinese emission regions. This is likely to be due to enhanced destruction of CO by OH. Overestimation of Asian ozone and its transport downwind implies that radiative forcing from this source may be overestimated. Model-observation discrepancies over Beijing do not appear to be due to emission controls linked to the Olympic Games in summer 2008.

With regard to aerosols, most models reproduce the satellite-derived AOD patterns over eastern China. Our study nevertheless reveals an overestimation of ECLIPSE model mean surface BC and sulphate aerosols in urban China in summer 2008. The effect of the short-term emission mitigation in Beijing is too weak to explain the differences between the models. Our results rather point to an overestimation of SO2 emissions, in particular, close to the surface in Chinese urban areas. However, we also identify a clear underestimation of aerosol concentrations over northern India, suggesting that the rapid recent growth of emissions in India, as well as their spatial extension, is underestimated in emission inventories. Model deficiencies in the representation of pollution accumulation due to the Indian monsoon may also be playing a role. Comparison with vertical aerosol lidar measurements highlights a general underestimation of scattering aerosols in the boundary layer associated with overestimation in the free troposphere pointing to modelled aerosol lifetimes that are too long. This is likely linked to too strong vertical transport and/or insufficient deposition efficiency during transport or export from the boundary layer, rather than chemical processing (in the case of sulphate aerosols). Underestimation of sulphate in the boundary layer implies potentially large errors in simulated aerosol-cloud interactions, via impacts on boundary-layer clouds.

This evaluation has important implications for accurate assessment of air pollutants on regional air quality and global climate based on global model calculations. Ideally, models should be run at higher resolution over source regions to better simulate urban-rural pollutant gradients and/or chemical regimes, and also to better resolve pollutant processing and loss by wet deposition as well as vertical transport. Discrepancies in vertical distributions require further quantification and improvement since these are a key factor in the determination of radiative forcing from short-lived pollutants.
BibTeX:
@article{QuennehenRautLawEtAl2016,
  author = {Quennehen, B. and Raut, J.-C. and Law, K.S. and Daskalakis, N. and Ancellet, G. and Clerbaux, C. and Kim, S.-W. and Lund, M.T. and Myhre, G. and Olivié, D.J.L. and Safieddine, S. and Skeie, R.B. and Thomas, J.L. and Tsyro, S. and Bazureau, A. and Bellouin, N. and Hu, M. and Kanakidou, M. and Klimont, Z. and Kupiainen, K. and Myriokefalitakis, S. and Quaas, J. and Rumbold, S.T. and Schulz, M. and Cherian, R. and Shimizu, A. and Wang, J. and Yoon, S.-C. and Zhu, T.},
  title = {Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10765-10792},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984920622&doi=10.5194%2facp-16-10765-2016&partnerID=40&md5=0c4411a2aa9ec719d38bb94c196f1e0c},
  doi = {10.5194/acp-16-10765-2016}
}
Abstract: Knowing the spatial and seasonal distributions of nitric acid (HNO3/ around the globe is of great interest and allows us to comprehend the processes regulating stratospheric ozone, especially in the polar regions. Due to its unprecedented spatial and temporal sampling, the nadir-viewing Infrared Atmospheric Sounding Interferometer (IASI) is capable of sounding the atmosphere twice a day globally, with good spectral resolution and low noise. With the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, we are retrieving, in near real time, columns as well as vertical profiles of several atmospheric species, among which is HNO3. We present in this paper the first characterization of the FORLI-HNO3 profile products, in terms of vertical sensitivity and error budgets. We show that the sensitivity of IASI to HNO3 is highest in the lower stratosphere (10-20 km), where the largest amounts of HNO3 are found, but that the vertical sensitivity of IASI only allows one level of information on the profile (degrees of freedom for signal, DOFS; ∼1). The sensitivity near the surface is negligible in most cases, and for this reason, a partial column (5-35 km) is used for the analyses. Both vertical profiles and partial columns are compared to FTIR ground-based measurements from the Network for the Detection of Atmospheric Composition Change (NDACC) to characterize the accuracy and precision of the FORLI-HNO3 product. The profile validation is conducted through the smoothing of the raw FTIR profiles by the IASI averaging kernels and gives good results, with a slight overestimation of IASI measurements in the upper troposphere/lower stratosphere (UTLS) at the six chosen stations (Thule, Kiruna, Jungfraujoch, Izaña, Lauder and Arrival Heights). The validation of the partial columns (5-35 km) is also conclusive with a mean correlation of 0.93 between IASI and the FTIR measurements. An initial survey of the HNO3 spatial and seasonal variabilities obtained from IASI measurements for a 1-year (2011) data set shows that the expected latitudinal gradient of concentrations from low to high latitudes and the large seasonal variability in polar regions (cycle amplitude around 30% of the seasonal signal, peak to peak) are well represented by IASI data. © Author(s) 2016.
BibTeX:
@article{RonsmansLangerockWespesEtAl2016,
  author = {Ronsmans, G. and Langerock, B. and Wespes, C. and Hannigan, J.W. and Hase, F. and Kerzenmacher, T. and Mahieu, E. and Schneider, M. and Smale, D. and Hurtmans, D. and De Mazière, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {First characterization and validation of FORLI-HNO3 vertical profiles retrieved from IASI/Metop},
  journal = {Atmospheric Measurement Techniques},
  year = {2016},
  volume = {9},
  pages = {4783-4801},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84989227460&doi=10.5194%2famt-9-4783-2016&partnerID=40&md5=27f5fc01eac08bf710a231d0e30eab3e},
  doi = {10.5194/amt-9-4783-2016}
}
Abstract: Satellite measurements from the thermal Infrared Atmospheric Sounding Interferometer (IASI), aircraft data from the MOZAIC/IAGOS project, as well as observations from ground-based stations, are used to assess the tropospheric ozone (O3) variability during the East Asian Summer Monsoon (EASM). Six years 2008-2013 of IASI data analysis reveals the ability of the instrument to detect the onset and the progression of the monsoon seen by a decrease in the tropospheric 0-6km O3 column due to the EASM, and to reproduce this decrease from one year to the other. The year-to-year variability is found to be mainly dependent on meteorology. Focusing on the period of May-August 2011, taken as an example year, IASI data show clear inverse relationship between tropospheric 0-6km O3 on one hand and meteorological parameters such as cloud cover, relative humidity and wind speed, on the other hand. Aircraft data from the MOZAIC/IAGOS project for the EASM of 2008-2013 are used to validate the IASI data and to assess the effect of the monsoon on the vertical distribution of the tropospheric O3 at different locations. Results show good agreement with a correlation coefficient of 0.73 (12%) between the 0-6km O3 column derived from IASI and aircraft data. IASI captures very well the inter-annual variation of tropospheric O3 observed by the aircraft data over the studied domain. Analysis of vertical profiles of the aircraft data shows a decrease in the tropospheric O3 that is more important in the free troposphere than in the boundary layer and at 10-20°N than elsewhere. Ground station data at different locations in India and China show a spatiotemporal dependence on meteorology during the monsoon, with a decrease up to 22ppbv in Hyderabad, and up to 5ppbv in the North China Plain. © Author(s) 2016.
BibTeX:
@article{SafieddineBoynardHaoEtAl2016,
  author = {Safieddine, S. and Boynard, A. and Hao, N. and Huang, F. and Wang, L. and Ji, D. and Barret, B. and Ghude, S.D. and Coheur, P.-F. and Hurtmans, D. and Clerbaux, C.},
  title = {Tropospheric ozone variability during the East Asian summer monsoon as observed by satellite (IASI), aircraft (MOZAIC) and ground stations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10489-10500},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983666721&doi=10.5194%2facp-16-10489-2016&partnerID=40&md5=158bf17112457c32a2655f82235fcdb0},
  doi = {10.5194/acp-16-10489-2016}
}
Abstract: The variability of atmospheric ammonia (NH3), emitted largely from agricultural sources, is an important factor when considering how inorganic fine particulate matter (PM2.5) concentrations and nitrogen cycling are changing over the United States. This study combines new observations of ammonia concentration from the surface, aboard aircraft, and retrieved by satellite to both evaluate the simulation of ammonia in a chemical transport model (GEOS-Chem) and identify which processes control the variability of these concentrations over a 5-year period (2008-2012). We find that the model generally underrepresents the ammonia concentration near large source regions (by 26% at surface sites) and fails to reproduce the extent of interannual variability observed at the surface during the summer (JJA). Variability in the base simulation surface ammonia concentration is dominated by meteorology (64%) as compared to reductions in SO2 and NOx emissions imposed by regulation (32%) over this period. Introduction of year-to-year varying ammonia emissions based on animal population, fertilizer application, and meteorologically driven volatilization does not substantially improve the model comparison with observed ammonia concentrations, and these ammonia emissions changes have little effect on the simulated ammonia concentration variability compared to those caused by the variability of meteorology and acid-precursor emissions. There is also little effect on the PM2.5 concentration due to ammonia emissions variability in the summer when gas-phase changes are favored, but variability in wintertime emissions, as well as in early spring and late fall, will have a larger impact on PM2.5 formation. This work highlights the need for continued improvement in both satellite-based and in situ ammonia measurements to better constrain the magnitude and impacts of spatial and temporal variability in ammonia concentrations. © 2016 The Author(s).
BibTeX:
@article{SchiferlHealdDammeEtAl2016,
  author = {Schiferl, L.D. and Heald, C.L. and Damme, M.V. and Clarisse, L. and Clerbaux, C. and Coheur, P.F. and Nowak, J.B. and Neuman, J.A. and Herndon, S.C. and Roscioli, J.R. and Eilerman, S.J.},
  title = {Interannual variability of ammonia concentrations over the United States: Sources and implications},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {12305-12328},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84989854884&doi=10.5194%2facp-16-12305-2016&partnerID=40&md5=5a4179475c124b8c17cd1ac3efe71e9f},
  doi = {10.5194/acp-16-12305-2016}
}
Abstract: The large-scale burning of crop residues in the North China Plain (NCP), one of the most densely populated world regions, was recently recognized to cause severe air pollution and harmful health effects. A reliable quantification of the magnitude of these fires is needed to assess regional air quality. Here, we use an eight-year record (2005-2012) of formaldehyde measurements from space to constrain the emissions of volatile organic compounds (VOCs) in this region. Using inverse modelling, we derive that satellite-based post-harvest burning fluxes are, on average, at least a factor of 2 higher than state-of-the-art bottom-up statistical estimates, although with significant interannual variability. Crop burning is calculated to cause important increases in surface ozone (+7%) and fine aerosol concentrations (+18%) in the North China Plain in June. The impact of crop fires is also found in satellite observations of other species, glyoxal, nitrogen dioxide and methanol, and we show that those measurements validate the magnitude of the top-down fluxes. Our study indicates that the top-down crop burning fluxes of VOCs in June exceed by almost a factor of 2 the combined emissions from other anthropogenic activities in this region, underscoring the need for targeted actions towards changes in agricultural management practices. © 2016 The Author(s).
BibTeX:
@article{StavrakouMuellerBauwensEtAl2016,
  author = {Stavrakou, T. and Müller, J.-F. and Bauwens, M. and De Smedt, I. and Lerot, C. and Van Roozendael, M. and Coheur, P.-F. and Clerbaux, C. and Boersma, K.F. and Van Der, A.R. and Song, Y.},
  title = {Substantial Underestimation of Post-Harvest Burning Emissions in the North China Plain Revealed by Multi-Species Space Observations},
  journal = {Scientific Reports},
  year = {2016},
  volume = {6},
  article number = {32307},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84985020806&doi=10.1038%2fsrep32307&partnerID=40&md5=214ae42dba634f4867b8976573e2707c},
  doi = {10.1038/srep32307}
}
Abstract: This paper studies the seasonal variation of surface and column CO at three different sites (Paris, Jungfraujoch and Wollongong), with an emphasis on establishing a link between the CO vertical distribution and the nature of CO emission sources. We find the first evidence of a time lag between surface and free tropospheric CO seasonal variations in the Northern Hemisphere. The CO seasonal variability obtained from the total columns and free tropospheric partial columns shows a maximum around March-April and a minimum around September-October in the Northern Hemisphere (Paris and Jungfraujoch). In the Southern Hemisphere (Wollongong) this seasonal variability is shifted by about 6 months. Satellite observations by the IASI-MetOp (Infrared Atmospheric Sounding Interferometer) and MOPITT (Measurements Of Pollution In The Troposphere) instruments confirm this seasonality. Ground-based FTIR (Fourier transform infrared) measurements provide useful complementary information due to good sensitivity in the boundary layer. In situ surface measurements of CO volume mixing ratios at the Paris and Jungfraujoch sites reveal a time lag of the near-surface seasonal variability of about 2 months with respect to the total column variability at the same sites. The chemical transport model GEOS-Chem (Goddard Earth Observing System chemical transport model) is employed to interpret our observations. GEOS-Chem sensitivity runs identify the emission sources influencing the seasonal variation of CO. At both Paris and Jungfraujoch, the surface seasonality is mainly driven by anthropogenic emissions, while the total column seasonality is also controlled by air masses transported from distant sources. At Wollongong, where the CO seasonality is mainly affected by biomass burning, no time shift is observed between surface measurements and total column data. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX:
@article{TeJeseckFrancoEtAl2016,
  author = {Té, Y. and Jeseck, P. and Franco, B. and Mahieu, E. and Jones, N. and Paton-Walsh, C. and Griffith, D.W.T. and Buchholz, R.R. and Hadji-Lazaro, J. and Hurtmans, D. and Janssen, C.},
  title = {Seasonal variability of surface and column carbon monoxide over the megacity Paris, high-altitude Jungfraujoch and Southern Hemispheric Wollongong stations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {10911-10925},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84985906373&doi=10.5194%2facp-16-10911-2016&partnerID=40&md5=6fc4e64d74c84b914c659cd99a5d75d1},
  doi = {10.5194/acp-16-10911-2016}
}
Abstract: In this paper, we assess how daily ozone (O3) measurements from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A platform can contribute to the analyses of the processes driving O3 variability in the troposphere and the stratosphere and, in the future, to the monitoring of long-term trends. The temporal evolution of O3 during the first 6 years of IASI (2008-2013) operation is investigated with multivariate regressions separately in four different layers (ground-300, 300-150, 150-25, 25-3ĝ€hPa), by adjusting to the daily time series averaged in 20° zonal bands, seasonal and linear trend terms along with important geophysical drivers of O3 variation (e.g. solar flux, quasi-biennial oscillation (QBO)). The regression model is shown to perform generally very well with a strong dominance of the annual harmonic terms and significant contributions from O3 drivers, in particular in the equatorial region where the QBO and the solar flux contribution dominate. More particularly, despite the short period of the IASI data set available up to now, two noticeable statistically significant apparent trends are inferred from the daily IASI measurements: a positive trend in the upper stratosphere (e.g. 1.74ĝ€±ĝ€0.77ĝ€DUĝ€yearĝ'1 between 30 and 50°ĝ€S), which is consistent with other studies suggesting a turnaround for stratospheric O3 recovery, and a negative trend in the troposphere at the mid-latitudes and high northern latitudes (e.g. ĝ'0.26ĝ€±ĝ€0.11ĝ€DUĝ€yearĝ'1 between 30 and 50°ĝ€N), especially during summer and probably linked to the impact of decreasing ozone precursor emissions. The impact of the high temporal sampling of IASI on the uncertainty in the determination of O3 trend has been further explored by performing multivariate regressions on IASI monthly averages and on ground-based Fourier transform infrared (FTIR) measurements. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX:
@article{WespesHurtmansKEmmonsEtAl2016,
  author = {Wespes, C. and Hurtmans, D. and K Emmons, L. and Safieddine, S. and Clerbaux, C. and Edwards, D.P. and Coheur, P.-F.},
  title = {Ozone variability in the troposphere and the stratosphere from the first 6 years of IASI observations (2008-2013)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2016},
  volume = {16},
  pages = {5721-5743},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84969838815&doi=10.5194%2facp-16-5721-2016&partnerID=40&md5=18ed8afaecfeb3a62177137a978429d4},
  doi = {10.5194/acp-16-5721-2016}
}
Abstract: In this paper, we describe a new flexible and robust NH3 retrieval algorithm from measurements of the Infrared Atmospheric Sounding Interferometer (IASI). The method is based on the calculation of a spectral hyperspectral range index (HRI) and subsequent conversion to NH3 columns via a neural network. It is an extension of the method presented in Van Damme et al. (2014a) who used lookup tables (LUT) for the radiance-concentration conversion. The new method inherits the advantages of the LUT-based method while providing several significant improvements. These include the following: (1) Complete temperature and humidity vertical profiles can be accounted for. (2) Third-party NH3 vertical profile information can be used. (3) Reported positive biases of LUT retrieval are reduced, and finally (4) a full measurement uncertainty characterization is provided. A running theme in this study, related to item (2), is the importance of the assumed vertical NH3 profile. We demonstrate the advantages of allowing variable profile shapes in the retrieval. As an example, we analyze how the retrievals change when all NH3 is assumed to be confined to the boundary layer. We analyze different averaging procedures in use for NH3 in the literature, introduced to cope with the variable measurement sensitivity and derive global averaged distributions for the year 2013. A comparison with a GEOS-Chem modeled global distribution is also presented, showing a general good correspondence (within ±3×1015 molecules.cm-2) over most of the Northern Hemisphere. However, IASI finds mean columns about 1-1.5×1016 molecules.cm-2 (∼50-60%) lower than GEOS-Chem for India and the North China plain. © 2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{WhitburnVanDammeClarisseEtAl2016,
  author = {Whitburn, S. and Van Damme, M. and Clarisse, L. and Bauduin, S. and Heald, C.L. and Hadji-Lazaro, J. and Hurtmans, D. and Zondlo, M.A. and Clerbaux, C. and Coheur, P.-F.},
  title = {A flexible and robust neural network IASI-NH3 retrieval algorithm},
  journal = {Journal of Geophysical Research},
  year = {2016},
  volume = {121},
  pages = {6581-6599},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977516702&doi=10.1002%2f2016JD024828&partnerID=40&md5=c8c04730faced6b2c947bc8b5a4db032},
  doi = {10.1002/2016JD024828}
}
Abstract: Among the atmospheric emission sources, wildfires are episodic events characterized by large spatial and temporal variability. Therefore, accurate information on gaseous and aerosol emissions from fires for specific regions and seasons is critical for air quality forecasts. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit provides fire observations over Africa and the Mediterranean with a temporal resolution of 15 min. It thus resolves the complete fire life cycle and captures the fires' peak intensities, which is not possible in Moderate Resolution Imaging Spectroradiometer (MODIS) fire emission inventories like the Global Fire Assimilation System (GFAS). We evaluate two different operational fire radiative power (FRP) products derived from SEVIRI, by studying a large forest fire in Antalya, Turkey, in July-August 2008. The EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) has higher FRP values during the fire episode than the Wildfire Automated Biomass Burning Algorithm (WF-ABBA). It is also in better agreement with the co-located, gridded MODIS FRP. Both products miss small fires that frequently occur in the region and are detected by MODIS. Emissions are derived from the FRP products. They are used along-side GFAS emissions in smoke plume simulations with the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. In comparisons with MODIS aerosol optical thickness (AOT) and Infrared Atmospheric Sounding Interferometer (IASI), CO and NH3 observations show that including the diurnal variability of fire emissions improves the spatial distribution and peak concentrations of the simulated smoke plumes associated with this large fire. They also show a large discrepancy between the currently available operational FRP products, with the LSA SAF being the most appropriate. © Author(s) 2015.
BibTeX:
@article{BaldassarrePozzoliSchmidtEtAl2015,
  author = {Baldassarre, G. and Pozzoli, L. and Schmidt, C.C. and Unal, A. and Kindap, T. and Menzel, W.P. and Whitburn, S. and Coheur, P.-F. and Kavgaci, A. and Kaiser, J.W.},
  title = {Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: A case study over Antalya in 2008},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {8539-8558},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938385241&doi=10.5194%2facp-15-8539-2015&partnerID=40&md5=9d4ad2e30b239a849cd9a6d2d45d148e},
  doi = {10.5194/acp-15-8539-2015}
}
Abstract: Among the atmospheric emission sources, wildfires are episodic events characterized by large spatial and temporal variability. Therefore, accurate information on fire gaseous and aerosol emissions for specific regions and seasons is critical for air quality forecasts. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit provides fire observations over Africa and the Mediterranean with a unique temporal resolution of 15min. It thus resolves the complete fire life cycle and captures the fires' peak intensities, which is not possible in MODIS-based fire emission inventories like GFAS. We evaluate two different operational Fire Radiative Power (FRP) products derived from SEVIRI, by studying the case of a large forest fire in Antalya, Turkey, in July-August 2008. The EUMETSAT LSA SAF product has higher FRP values during the fire episode than the WF-ABBA product. It is also in better agreement with the colocated, gridded MODIS FRP. Both products miss small fires that frequently occur in the region and are detected by MODIS. Emissions are derived from the FRP products. They are used along-side GFAS emissions in smoke plume simulations with WRF and the Community Multiscale Air Quality model (CMAQ). Comparisons with MODIS AOT and IASI CO and NH3 observations show that including the diurnal variability of fire emissions improves the spatial distribution and peak concentrations of the simulated smoke plumes associated to the large fire. They also show a large discrepancy between the currently available operational FRP products, with the LSA SAF one being the most appropriate. © Author(s) 2015. CC Attribution 3.0 License.
BibTeX:
@article{BaldassarrePozzoliSchmidtEtAl2015a,
  author = {Baldassarre, G. and Pozzoli, L. and Schmidt, C.C. and Unal, A. and Kindap, T. and Menzel, W.P. and Whitburn, S. and Coheur, P.-F. and Kavgaci, A. and Kaiser, J.W.},
  title = {Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: The case of Antalya in 2008},
  journal = {Atmospheric Chemistry and Physics Discussions},
  year = {2015},
  volume = {15},
  pages = {1-46},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930484248&doi=10.5194%2facpd-15-1-2015&partnerID=40&md5=a009f0006f183c7f8dc01441d7c62264},
  doi = {10.5194/acpd-15-1-2015}
}
Abstract: We show the results and evaluation with independent measurements from assimilating both MOPITT (Measurements Of Pollution In The Troposphere) and IASI (Infrared Atmospheric Sounding Interferometer) retrieved profiles into the Community Earth System Model (CESM). We used the Data Assimilation Research Testbed ensemble Kalman filter technique, with the full atmospheric chemistry CESM component Community Atmospheric Model with Chemistry. We first discuss the methodology and evaluation of the current data assimilation system with coupled meteorology and chemistry data assimilation. The different capabilities of MOPITT and IASI retrievals are highlighted, with particular attention to instrument vertical sensitivity and coverage and how these impact the analyses. MOPITT and IASI CO retrievals mostly constrain the CO fields close to the main anthropogenic, biogenic, and biomass burning CO sources. In the case of IASI CO assimilation, we also observe constraints on CO far from the sources. During the simulation time period (June and July 2008), CO assimilation of both instruments strongly improves the atmospheric CO state as compared to independent observations, with the higher spatial coverage of IASI providing better results on the global scale. However, the enhanced sensitivity of multispectral MOPITT observations to near surface CO over the main source regions provides synergistic effects at regional scales. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BarreGaubertArellanoEtAl2015,
  author = {Barré, J. and Gaubert, B. and Arellano, A.F.J. and Worden, H.M. and Edwards, D.P. and Deeter, M.N. and Anderson, J.L. and Raeder, K. and Collins, N. and Tilmes, S. and Francis, G. and Clerbaux, C. and Emmons, L.K. and Pfister, G.G. and Coheur, P.-F. and Hurtmans, D.},
  title = {Assessing the impacts of assimilating IASI and MOPITT CO retrievals using CESM-CAM-chem and DART},
  journal = {Journal of Geophysical Research},
  year = {2015},
  volume = {120},
  pages = {10501-10529},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945307190&doi=10.1002%2f2015JD023467&partnerID=40&md5=363c3062663a9378a87af0b4953fa6c0},
  doi = {10.1002/2015JD023467}
}
Abstract: Sulfur-rich degassing, which is mostly composed of sulfur dioxide (SO2), plays a major role in the overall impact of volcanism on the atmosphere and climate. The accurate assessment of this impact is currently hampered by the poor knowledge of volcanic SO2 emissions. Here, using an inversion procedure, we show how assimilating snapshots of the volcanic SO2 load derived from the Infrared Atmospheric Sounding Interferometer (IASI) allows for reconstructing both the flux and altitude of the SO2 emissions with an hourly resolution. For this purpose, the regional chemistry-transport model CHIMERE is used to describe the dispersion of SO2 when released in the atmosphere. As proof of concept, we study the 10 April 2011 eruption of the Etna volcano (Italy), which represents one of the few volcanoes instrumented on the ground for the continuous monitoring of SO2 degassing. We find that the SO2 flux time-series retrieved from satellite imagery using the inverse scheme is in agreement with ground observations during ash-poor phases of the eruption. However, large discrepancies are observed during the ash-rich paroxysmal phase as a result of enhanced plume opacity affecting ground-based ultraviolet (UV) spectroscopic retrievals. As a consequence, the SO2 emission rate derived from the ground is underestimated by almost one order of magnitude. Altitudes of the SO2 emissions predicted by the inverse scheme are validated against an RGB image of the Moderate Resolution Imaging Spectroradiometer (MODIS) capturing the near-source atmospheric pathways followed by Etna plumes, in combination with forward trajectories from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. At a large distance from the source, modelled SO2 altitudes are compared with independent information on the volcanic cloud height. We find that the altitude predicted by the inverse scheme is in agreement with snapshots of the SO2 height retrieved from recent algorithms exploiting the high spectral resolution of IASI. The validity of the modelled SO2 altitude is further confirmed by the detection of a layer of particles at the same altitude by the spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Analysis of CALIOP colour and depolarization ratios suggests that these particles consist of sulfate aerosols formed from precursory volcanic SO2. The reconstruction of emission altitude, through inversion procedures which assimilate volcanic SO2 column amounts, requires specific meteorological conditions, especially sufficient wind shear so that gas parcels emitted at different altitudes follow distinct trajectories. We consequently explore the possibility and limits of assimilating in inverse schemes infrared (IR) imagery of the volcanic SO2 cloud altitude which will render the inversion procedure independent of the wind shear prerequisite. © Author(s) 2015.
BibTeX:
@article{BoichuClarissePereEtAl2015,
  author = {Boichu, M. and Clarisse, L. and Péré, J.-C. and Herbin, H. and Goloub, P. and Thieuleux, F. and Ducos, F. and Clerbaux, C. and Tanré, D.},
  title = {Temporal variations of flux and altitude of sulfur dioxide emissions during volcanic eruptions: Implications for long-range dispersal of volcanic clouds},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {8381-8400},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938381597&doi=10.5194%2facp-15-8381-2015&partnerID=40&md5=f25f9ad2289df9a066a1d0d0849306b0},
  doi = {10.5194/acp-15-8381-2015}
}
Abstract: During 7-12 July 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapor isotopic composition using surface in situ observations in Bermuda Island, South Greenland coast (Ivittuut), and northwest Greenland ice sheet (NEEM), as well as remote sensing observations (Infrared Atmospheric Sounding Interferometer (IASI) instrument on board MetOp-A), depicting propagation of similar surface and midtropospheric humidity and δD signals. Simulations using Lagrangian moisture source diagnostic and water tagging in a regional model showed that Greenland was affected by an atmospheric river transporting moisture from the western subtropical North Atlantic Ocean, which is coherent with observations of snow pit impurities deposited at NEEM. At Ivittuut, surface air temperature, humidity, and δD increases are observed. At NEEM, similar temperature increase is associated with a large and long-lasting ~100‰δD enrichment and ~15‰ deuterium excess decrease, thereby reaching Ivittuut level. We assess the simulation of this event in two isotope-enabled atmospheric general circulation models (LMDz-iso and ECHAM5-wiso). LMDz-iso correctly captures the timing of propagation for this event identified in IASI data but depict too gradual variations when compared to surface data. Both models reproduce the surface meteorological and isotopic values during the event but underestimate the background deuterium excess at NEEM. Cloud liquid water content parametrization in LMDz-iso poorly impacts the vapor isotopic composition. Our data demonstrate that during this atmospheric river event the deuterium excess signal is conserved from the moisture source to northwest Greenland. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BonneSteen-LarsenRisiEtAl2015,
  author = {Bonne, J.-L. and Steen-Larsen, H.C. and Risi, C. and Werner, M. and Sodemann, H. and Lacour, J.-L. and Fettweis, X. and Cesana, G. and Delmotte, M. and Cattani, O. and Vallelonga, P. and Kjær, H.A. and Clerbaux, C. and Sveinbjörnsdóttir, Á.E. and Masson-Delmotte, V.},
  title = {The summer 2012 Greenland heat wave: In situ and remote sensing observations of water vapor isotopic composition during an atmospheric river event},
  journal = {Journal of Geophysical Research},
  year = {2015},
  volume = {120},
  pages = {2970-2989},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84928611420&doi=10.1002%2f2014JD022602&partnerID=40&md5=10de53112c870bfe5632fb125221678d},
  doi = {10.1002/2014JD022602}
}
Abstract: The IASI mission flying onboard the MetOp satellites has been providing global observations of the air composition twice a day since 2007. From the atmospheric spectra recorded by the instruments in the thermal infrared spectral range, concentrations of a series of trace gases can be monitored, enhanced levels of pollution can be detected, and particle types can be determined to some extent. This paper recalls the historical context for the IASI remote sensor, reviews its capability to observe some key species for global and regional pollution monitoring, and reports on information services that benefit from the mission. © 2015 Academie des sciences
BibTeX:
@article{ClerbauxHadji-LazaroTurquetyEtAl2015,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Turquety, S. and George, M. and Boynard, A. and Pommier, M. and Safieddine, S. and Coheur, P.-F. and Hurtmans, D. and Clarisse, L. and Van Damme, M.},
  title = {Tracking pollutants from space: Eight years of IASI satellite observation},
  journal = {Comptes Rendus - Geoscience},
  year = {2015},
  volume = {347},
  pages = {134-144},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947019097&doi=10.1016%2fj.crte.2015.06.001&partnerID=40&md5=291085ee4ae78125380ab0a893944842},
  doi = {10.1016/j.crte.2015.06.001}
}
Abstract: We present a retrieval method for ammonia (NH3) total columns from ground-based Fourier transform infrared (FTIR) observations. Observations from Bremen (53.10° N, 8.85° E), Lauder (45.04° S, 169.68° E), Reúnion (20.9° S, 55.50° E) and Jungfraujoch (46.55° N, 7.98° E) were used to illustrate the capabilities of the method. NH3 mean total columns ranging 3 orders of magnitude were obtained, with higher values at Bremen (mean of 13.47 × 1015 molecules cm-2) and lower values at Jungfraujoch (mean of 0.18 × 1015 molecules cm-2). In conditions with high surface concentrations of ammonia, as in Bremen, it is possible to retrieve information on the vertical gradient, as two layers can be distinguished. The retrieval there is most sensitive to ammonia in the planetary boundary layer, where the trace gas concentration is highest. For conditions with low concentrations, only the total column can be retrieved. Combining the systematic and random errors we have a mean total error of 26 % for all spectra measured at Bremen (number of spectra (N)= 554), 30 % for all spectra from Lauder (N = 2412), 25 % for spectra from Reúnion (N = 1262) and 34 % for spectra measured at Jungfraujoch (N = 2702). The error is dominated by the systematic uncertainties in the spectroscopy parameters. Station-specific seasonal cycles were found to be consistent with known seasonal cycles of the dominant ammonia sources in the station surroundings. The developed retrieval methodology from FTIR instruments provides a new way of obtaining highly time-resolved measurements of ammonia burdens. FTIR-NH3 observations will be useful for understanding the dynamics of ammonia concentrations in the atmosphere and for satellite and model validation. It will also provide additional information to constrain the global ammonia budget. © 2015 Author(s).
BibTeX:
@article{DammersVigourouxPalmEtAl2015,
  author = {Dammers, E. and Vigouroux, C. and Palm, M. and Mahieu, E. and Warneke, T. and Smale, D. and Langerock, B. and Franco, B. and Van Damme, M. and Schaap, M. and Notholt, J. and Erisman, J.W.},
  title = {Retrieval of ammonia from ground-based FTIR solar spectra},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {12789-12803},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947784676&doi=10.5194%2facp-15-12789-2015&partnerID=40&md5=a076e78fab28e61490ca7cea5a4d2147},
  doi = {10.5194/acp-15-12789-2015}
}
Abstract: We present a retrieval method for ammonia (NH3) total columns from ground-based Fourier Transform InfraRed (FTIR) observations. Observations from Bremen (53.10° N, 8.85° E), Lauder (45.04° S, 169.68° E), Reunion (20.9° S, 55.50 ° E) and Jungfraujoch (46.55° N, 7.98° E) were used to illustrate the capabilities of the method. NH3 mean total columns ranging three orders of magnitude were obtained with higher values at Bremen (mean of 13.47 × 1015 molecules cm-2) to the lower values at Jungfraujoch (mean of 0.18 × 1015 molecules cm-2). In conditions with high surface concentrations of ammonia, as in Bremen, it is possible to retrieve information on the vertical gradient as two layers can be discriminated. The retrieval there is most sensitive to ammonia in the planetary boundary layer, where the trace gas concentration is highest. For conditions with low concentrations only the total column can be retrieved. Combining the systematic and random errors we have a mean total error of 26 % for all spectra measured at Bremen (Number of spectra (N) Combining double low line 554), 30 % for all spectra from Lauder (N Combining double low line2412), 25 % for spectra from Reunion (N Combining double low line1262) and 34 % for spectra measured at Jungfraujoch (N Combining double low line2702). The error is dominated by the systematic uncertainties in the spectroscopy parameters. Station specific seasonal cycles were found to be consistent with known seasonal cycles of the dominant ammonia sources in the station surroundings. The developed retrieval methodology from FTIR-instruments provides a new way to obtain highly time-resolved measurements of ammonia burdens. FTIR-NH3 observations will be useful for understanding the dynamics of ammonia concentrations in the atmosphere and for satellite and model validation. It will also provide additional information to constrain the global ammonia budget. © Author(s) 2015.
BibTeX:
@article{DammersVigourouxPalmEtAl2015a,
  author = {Dammers, E. and Vigouroux, C. and Palm, M. and Mahieu, E. and Warneke, T. and Smale, D. and Langerock, B. and Franco, B. and Van Damme, M. and Schaap, M. and Notholt, J. and Erisman, J.W.},
  title = {Retrieval of ammonia from ground-based FTIR solar spectra},
  journal = {Atmospheric Chemistry and Physics Discussions},
  year = {2015},
  volume = {15},
  pages = {23279-23315},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042579255&doi=10.5194%2facpd-15-23279-2015&partnerID=40&md5=a6ad9c3f7fc19f1193c378be1268eb2b},
  doi = {10.5194/acpd-15-23279-2015}
}
Abstract: Ozone is an important greenhouse gas in terms of anthropogenic radiative forcing (RF). RF calculations for ozone were until recently entirely model based, and significant discrepancies were reported due to different model characteristics. However, new instantaneous radiative kernels (IRKs) calculated from hyperspectral thermal IR satellites have been able to help adjudicate between different climate model RF calculations. IRKs are defined as the sensitivity of the outgoing longwave radiation (OLR) flux with respect to the ozone vertical distribution in the full 9.6 μm band. Previous methods applied to measurements from the Tropospheric Emission Spectrometer (TES) on Aura rely on an anisotropy approximation for the angular integration. In this paper, we present a more accurate but more computationally expensive method to calculate these kernels. The method of direct integration is based on similar principles to the anisotropy approximation, but it deals more precisely with the integration of the Jacobians. We describe both methods and highlight their differences with respect to the IRKs and the ozone longwave radiative effect (LWRE), i.e., the radiative impact in OLR due to absorption by ozone, for both tropospheric and total columns, from measurements of the Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp-A. Biases between the two methods vary from -25 to +20 % for the LWRE, depending on the viewing angle. These biases point to the inadequacy of the anisotropy method, especially at nadir, suggesting that the TES-derived LWREs are biased low by around 25 % and that chemistry-climate model OLR biases with respect to TES are underestimated. In this paper we also exploit the sampling performance of IASI to obtain first daily global distributions of the LWRE, for 12 days (the 15th of each month) in 2011, calculated with the direct integration method. We show that the temporal variation of global and latitudinal averages of the LWRE shows patterns which are controlled by changes in the surface temperature and ozone variation due to specific processes, such as the ozone hole in the polar regions and stratospheric intrusions into the troposphere. © Author(s) 2015.
BibTeX:
@article{DonikiHurtmansClarisseEtAl2015,
  author = {Doniki, S. and Hurtmans, D. and Clarisse, L. and Clerbaux, C. and Worden, H.M. and Bowman, K.W. and Coheur, P.-F.},
  title = {Instantaneous longwave radiative impact of ozone: An application on IASI/MetOp observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {12971-12987},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84948472675&doi=10.5194%2facp-15-12971-2015&partnerID=40&md5=73b38e85e0040888bd3949282db664b9},
  doi = {10.5194/acp-15-12971-2015}
}
Abstract: We present global distributions of C2H2 and hydrogen cyanide (HCN) total columns derived from the Infrared Atmospheric Sounding Interferometer (IASI) for the years 2008-2010. These distributions are obtained with a fast method allowing to retrieve C2H2 abundance globally with a 5 % precision and HCN abundance in the tropical (subtropical) belt with a 10 % (25 %) precision. IASI data are compared for validation purposes with ground-based Fourier transform infrared (FTIR) spectrometer measurements at four selected stations. We show that there is an overall agreement between the ground-based and space measurements with correlation coefficients for daily mean measurements ranging from 0.28 to 0.81, depending on the site. Global C2H2 and subtropical HCN abundances retrieved from IASI spectra show the expected seasonality linked to variations in the anthropogenic emissions and seasonal biomass burning activity, as well as exceptional events, and are in good agreement with previous spaceborne studies. Total columns simulated by the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) are compared to the ground-based FTIR measurements at the four selected stations. The model is able to capture the seasonality in the two species in most of the cases, with correlation coefficients for daily mean measurements ranging from 0.50 to 0.86, depending on the site. IASI measurements are also compared to the distributions from MOZART-4. Seasonal cycles observed from satellite data are reasonably well reproduced by the model with correlation coefficients ranging from g'0.31 to 0.93 for C2H2 daily means, and from 0.09 to 0.86 for HCN daily means, depending on the considered region. However, the anthropogenic (biomass burning) emissions used in the model seem to be overestimated (underestimated), and a negative global mean bias of 1 % (16 %) of the model relative to the satellite observations was found for C2H2 (HCN). © Author(s) 2015.
BibTeX:
@article{DuflotWespesClarisseEtAl2015,
  author = {Duflot, V. and Wespes, C. and Clarisse, L. and Hurtmans, D. and Ngadi, Y. and Jones, N. and Paton-Walsh, C. and Hadji-Lazaro, J. and Vigouroux, C. and De Mazière, M. and Metzger, J.-M. and Mahieu, E. and Servais, C. and Hase, F. and Schneider, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {Acetylene (C2H2) and hydrogen cyanide (HCN) from IASI satellite observations: Global distributions, validation, and comparison with model},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {10509-10527},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84942799712&doi=10.5194%2facp-15-10509-2015&partnerID=40&md5=bf6ec972df62c80ea74390aa699beea4},
  doi = {10.5194/acp-15-10509-2015}
}
Abstract: An overview of the achievements and the current state of knowledge on reactive nitrogen in Europe, focusing on deposition, critical load exceedances, and modeled and measured trends.
BibTeX:
@article{ErismanDammersVanDammeEtAl2015,
  author = {Erisman, J.W. and Dammers, E. and Van Damme, M. and Soudzilovskaia, N. and Schaap, M.},
  title = {Trends in EU nitrogen deposition and impacts on ecosystems},
  journal = {EM: Air and Waste Management Association's Magazine for Environmental Managers},
  year = {2015},
  volume = {65},
  pages = {31-35},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940495842&partnerID=40&md5=18262d8756fcafd0863423b860aff767}
}
Abstract: An improved spectroscopy is used to implement and optimize the retrieval strategy of ethane (C2H6) from ground-based Fourier Transform Infrared (FTIR) solar spectra recorded at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580m a.s.l.). The improved spectroscopic parameters include C2H6 pseudo-lines in the 2720-3100cm-1 range and updated line parameters for methyl chloride and ozone. These improved spectroscopic parameters allow for substantial reduction of the fitting residuals as well as enhanced information content. They also contribute to limiting oscillations responsible for ungeophysical negative mixing ratio profiles. This strategy has been successfully applied to the Jungfraujoch solar spectra available from 1994 onwards. The resulting time series is compared with C2H6 total columns simulated by the state-of-the-art chemical transport model GEOS-Chem. Despite very consistent seasonal cycles between both data sets, a negative systematic bias relative to the FTIR observations suggests that C2H6 emissions are underestimated in the current inventories implemented in GEOS-Chem. Finally, C2H6 trends are derived from the FTIR time series, revealing a statistically-significant sharp increase of the C2H6 burden in the remote atmosphere above Jungfraujoch since 2009. Evaluating cause of this change in the C2H6 burden, which may be related to the recent massive growth of shale gas exploitation in North America, is of primary importance for atmospheric composition and air quality in the Northern Hemisphere. © 2015 Elsevier Ltd.
BibTeX:
@article{FrancoBaderToonEtAl2015,
  author = {Franco, B. and Bader, W. and Toon, G.C. and Bray, C. and Perrin, A. and Fischer, E.V. and Sudo, K. and Boone, C.D. and Bovy, B. and Lejeune, B. and Servais, C. and Mahieu, E.},
  title = {Retrieval of ethane from ground-based FTIR solar spectra using improved spectroscopy: Recent burden increase above Jungfraujoch},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2015},
  volume = {160},
  pages = {36-49},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926160061&doi=10.1016%2fj.jqsrt.2015.03.017&partnerID=40&md5=461fe56b36b436f77347fd44af5407fc},
  doi = {10.1016/j.jqsrt.2015.03.017}
}
Abstract: As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR) solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010–December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.). Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs), GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6–8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation. © Author(s) 2015.
BibTeX:
@article{FrancoHendrickVanRoozendaelEtAl2015,
  author = {Franco, B. and Hendrick, F. and Van Roozendael, M. and Müller, J.-F. and Stavrakou, T. and Marais, E.A. and Bovy, B. and Bader, W. and Fayt, C. and Hermans, C. and Lejeune, B. and Pinardi, G. and Servais, C. and Mahieu, E.},
  title = {Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {1733-1756},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84928492418&doi=10.5194%2famt-8-1733-2015&partnerID=40&md5=8a1c5f1355099567e9b41cfa1925fe26},
  doi = {10.5194/amt-8-1733-2015}
}
Abstract: Carbon monoxide (CO) is a key atmospheric compound that can be remotely sensed by satellite on the global scale. Fifteen years of continuous observations are now available from the MOPITT/Terra mission (2000 to present). Another 15 and more years of observations will be provided by the IASI/MetOp instrument series (2007-2023 >). In order to study long-term variability and trends, a homogeneous record is required, which is not straightforward as the retrieved quantities are instrument and processing dependent. The present study aims at evaluating the consistency between the CO products derived from the MOPITT and IASI missions, both for total columns and vertical profiles, during a 6-year overlap period (2008-2013). The analysis is performed by first comparing the available 2013 versions of the retrieval algorithms (v5T for MOPITT and v20100815 for IASI), and second using a dedicated reprocessing of MOPITT CO profiles and columns using the same a priori information as the IASI product. MOPITT total columns are generally slightly higher over land (bias ranging from 0 to 13 %) than IASI data. When IASI and MOPITT data are retrieved with the same a priori constraints, correlation coefficients are slightly improved. Large discrepancies (total column bias over 15 %) observed in the Northern Hemisphere during the winter months are reduced by a factor of 2 to 2.5. The detailed analysis of retrieved vertical profiles compared with collocated aircraft data from the MOZAIC-IAGOS network, illustrates the advantages and disadvantages of a constant vs. a variable a priori. On one hand, MOPITT agrees better with the aircraft profiles for observations with persisting high levels of CO throughout the year due to pollution or seasonal fire activity (because the climatology-based a priori is supposed to be closer to the real atmospheric state). On the other hand, IASI performs better when unexpected events leading to high levels of CO occur, due to a larger variability associated with the a priori. © 2015 Author(s).
BibTeX:
@article{GeorgeClerbauxBouararEtAl2015,
  author = {George, M. and Clerbaux, C. and Bouarar, I. and Coheur, P.-F. and Deeter, M.N. and Edwards, D.P. and Francis, G. and Gille, J.C. and Hadji-Lazaro, J. and Hurtmans, D. and Inness, A. and Mao, D. and Worden, H.M.},
  title = {An examination of the long-term CO records from MOPITT and IASI: Comparison of retrieval methodology},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {4313-4328},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944707174&doi=10.5194%2famt-8-4313-2015&partnerID=40&md5=40a0a0acbd5e8d833c78136bde201456},
  doi = {10.5194/amt-8-4313-2015}
}
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI) flying onboard MetOpA and MetOpB is able to capture fine isotopic variations of the HDO to H2O ratio (δD) in the troposphere. Such observations at the high spatio-temporal resolution of the sounder are of great interest to improve our understanding of the mechanisms controlling humidity in the troposphere. In this study we aim to empirically assess the validity of our error estimation previously evaluated theoretically. To achieve this, we compare IASI δD retrieved profiles with other available profiles of δD, from the TES infrared sounder onboard AURA and from three ground-based FTIR stations produced within the MUSICA project: the NDACC (Network for the Detection of Atmospheric Composition Change) sites Kiruna and Izaña, and the TCCON site Karlsruhe, which in addition to near-infrared TCCON spectra also records mid-infrared spectra. We describe the achievable level of agreement between the different retrievals and show that these theoretical errors are in good agreement with empirical differences. The comparisons are made at different locations from tropical to Arctic latitudes, above sea and above land. Generally IASI and TES are similarly sensitive to δD in the free troposphere which allows one to compare their measurements directly. At tropical latitudes where IASI's sensitivity is lower than that of TES, we show that the agreement improves when taking into account the sensitivity of IASI in the TES retrieval. For the comparison IASI-FTIR only direct comparisons are performed because the sensitivity profiles of the two observing systems do not allow to take into account their differences of sensitivity. We identify a quasi negligible bias in the free troposphere (-3 ‰) between IASI retrieved δD with the TES, which are bias corrected, but important with the ground-based FTIR reaching -47 ‰. We also suggest that model-satellite observation comparisons could be optimized with IASI thanks to its high spatial and temporal sampling. © Author(s) 2015.
BibTeX:
@article{LacourClarisseWordenEtAl2015,
  author = {Lacour, J.-L. and Clarisse, L. and Worden, J. and Schneider, M. and Barthlott, S. and Hase, F. and Risi, C. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {Cross-validation of IASI/MetOp derived tropospheric δd with TES and ground-based FTIR observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {1447-1466},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925435229&doi=10.5194%2famt-8-1447-2015&partnerID=40&md5=5663da6d9ac8ea859d25d40bf11a94cb},
  doi = {10.5194/amt-8-1447-2015}
}
BibTeX:
@article{Predoi-CrossLiuMurphyEtAl2015,
  author = {Predoi-Cross, A. and Liu, W. and Murphy, R. and Povey, C. and Gamache, R. and Laraia, A. and McKellar, A.R.W. and Hurtmans, D. and Devi, V.M.},
  title = {Corrigendum to "Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012-00001 and 30013-00001 bands" [J. Quant. Spectrosc. Radiat. Transf., 111 (9) (2010) 1065-1079] doi: 10.1016/j.jqsrt.2010.01.003},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2015},
  volume = {164},
  pages = {256},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937967512&doi=10.1016%2fj.jqsrt.2015.06.017&partnerID=40&md5=82e6a4a358bfb9fc7b120cf911b5fa07},
  doi = {10.1016/j.jqsrt.2015.06.017}
}
Abstract: Satellite measurements from the thermal Infrared Atmospheric Sounding Interferometer (IASI), the Measurements of OZone and water vapor by in-service AIrbus airCraft (MOZAIC), as well as observations from ground based stations, are used to assess the tropospheric ozone (O3) variability during the East Asian Summer Monsoon (EASM). Six years [2008-2013] of IASI data analysis reveals the ability of the instrument to detect the onset and the progression of the monsoon reflected by a decrease in the tropospheric [0-6] km O3 column due to the EASM, and to reproduce this decrease from one year to the other. Focusing on the period of May-August 2011, taken as an example year, IASI data show clear inverse relationship between tropospheric [0-6] km O3 on one hand and meteorological parameters such as cloud cover, relative humidity and wind speed, on the other hand. Aircraft data from the MOZAIC project at Hyderabad, Nanjing and Guangzhou are used to validate the IASI data and to assess the effect of the monsoon on the vertical distribution of the tropospheric O3 at different locations. Results show good agreement with a correlation coefficient of 0.74 between the [0-6] km O3 column derived from IASI and MOZAIC. The aircraft data show a decrease in the tropospheric O3 that is more important in the free troposphere than in the boundary layer and at Hyderabad than at the other two Chinese cities. Ground station data at different locations in India and China show a spatiotemporal dependence on meteorology during the monsoon, with decrease up to 22 ppbv in Hyderabad, and up to 5 ppbv in the North China Plain. © Author(s) 2015.
BibTeX:
@article{SafieddineBoynardHaoEtAl2015,
  author = {Safieddine, S. and Boynard, A. and Hao, N. and Huang, F. and Wang, L. and Ji, D. and Barret, B. and Ghude, S.D. and Coheur, P.-F. and Hurtmans, D. and Clerbaux, C.},
  title = {Tropospheric Ozone Variability during the East Asian Summer Monsoon as Observed by Satellite (IASI), Aircraft (MOZAIC) and Ground Stations},
  journal = {Atmospheric Chemistry and Physics Discussions},
  year = {2015},
  volume = {15},
  pages = {31925-31950},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984918685&doi=10.5194%2facpd-15-31925-2015&partnerID=40&md5=f5d27f226b717c5c945cb9f6f0c89cf2},
  doi = {10.5194/acpd-15-31925-2015}
}
Abstract: The vertical columns of formaldehyde (HCHO) retrieved from two satellite instruments, the Global Ozone Monitoring Instrument-2 (GOME-2) on Metop-A and the Ozone Monitoring Instrument (OMI) on Aura, are used to constrain global emissions of HCHO precursors from open fires, vegetation and human activities in the year 2010. To this end, the emissions are varied and optimized using the adjoint model technique in the IMAGESv2 global CTM (chemical transport model) on a monthly basis and at the model resolution. Given the different local overpass times of GOME-2 (09:30 LT) and OMI (13:30 LT), the simulated diurnal cycle of HCHO columns is investigated and evaluated against ground-based optical measurements at seven sites in Europe, China and Africa. The modeled diurnal cycle exhibits large variability, reflecting competition between photochemistry and emission variations, with noon or early afternoon maxima at remote locations (oceans) and in regions dominated by anthropogenic emissions, late afternoon or evening maxima over fire scenes, and midday minima in isoprene-rich regions. The agreement between simulated and ground-based columns is generally better in summer (with a clear afternoon maximum at mid-latitude sites) than in winter, and the annually averaged ratio of afternoon to morning columns is slightly higher in the model (1.126) than in the ground-based measurements (1.043). The anthropogenic VOC (volatile organic compound) sources are found to be weakly constrained by the inversions on the global scale, mainly owing to their generally minor contribution to the HCHO columns, except over strongly polluted regions, like China. The OMI-based inversion yields total flux estimates over China close to the bottom-up inventory (24.6 vs. 25.5 TgVOC yrg-1 in the a priori) with, however, pronounced increases in the northeast of China and reductions in the south. Lower fluxes are estimated based on GOME-2 HCHO columns (20.6 TgVOC yrg-1), in particular over the northeast, likely reflecting mismatches between the observed and the modeled diurnal cycle in this region. The resulting biogenic and pyrogenic flux estimates from both optimizations generally show a good degree of consistency. A reduction of the global annual biogenic emissions of isoprene is derived, of 9 and 13 % according to GOME-2 and OMI, respectively, compared to the a priori estimate of 363 Tg in 2010. The reduction is largest (up to 25-40 %) in the Southeastern US, in accordance with earlier studies. The GOME-2 and OMI satellite columns suggest a global pyrogenic flux decrease by 36 and 33 %, respectively, compared to the GFEDv3 (Global Fire Emissions Database) inventory. This decrease is especially pronounced over tropical forests, such as in Amazonia, Thailand and Myanmar, and is supported by comparisons with CO observations from IASI (Infrared Atmospheric Sounding Interferometer). In contrast to these flux reductions, the emissions due to harvest waste burning are strongly enhanced over the northeastern China plain in June (by ca. 70 % in June according to OMI) as well as over Indochina in March. Sensitivity inversions showed robustness of the inferred estimates, which were found to lie within 7 % of the standard inversion results at the global scale. © Author(s) 2015.
BibTeX:
@article{StavrakouMuellerBauwensEtAl2015,
  author = {Stavrakou, T. and Müller, J.-F. and Bauwens, M. and De Smedt, I. and Van Roozendael, M. and De Mazière, M. and Vigouroux, C. and Hendrick, F. and George, M. and Clerbaux, C. and Coheur, P.-F. and Guenther, A.},
  title = {How consistent are top-down hydrocarbon emissions based on formaldehyde observations from GOME-2 and OMI?},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {11861-11884},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946094222&doi=10.5194%2facp-15-11861-2015&partnerID=40&md5=ebe95c5321dcebf1da87802ec8257eb4},
  doi = {10.5194/acp-15-11861-2015}
}
Abstract: We present a new data set of sulfur dioxide (SO2) vertical columns from observations of the Ozone Monitoring Instrument (OMI)/AURA instrument between 2004 and 2013. The retrieval algorithm used is an advanced Differential Optical Absorption Spectroscopy (DOAS) scheme combined with radiative transfer calculation. It is developed in preparation for the operational processing of SO2 data product for the upcoming TROPOspheric Monitoring Instrument/Sentinel 5 Precursor mission. We evaluate the SO2 column results with those inferred from other satellite retrievals such as Infrared Atmospheric Sounding Interferometer and OMI (Linear Fit and Principal Component Analysis algorithms). A general good agreement between the different data sets is found for both volcanic and anthropogenic SO2 emission scenarios. We show that our algorithm produces SO2 columns with low noise and is able to provide accurate estimates of SO2. This conclusion is supported by important validation results over the heavily polluted site of Xianghe (China). Nearly 4 years of OMI and ground-based multiaxis DOAS SO2 columns are compared, and an excellent match is found. We also highlight the improved performance of the algorithm in capturing weak SO2 sources by detecting shipping SO2 emissions in long-term averaged data, an unreported measurement from space. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{TheysDeSmedtVanGentEtAl2015,
  author = {Theys, N. and De Smedt, I. and Van Gent, J. and Danckaert, T. and Wang, T. and Hendrick, F. and Stavrakou, T. and Bauduin, S. and Clarisse, L. and Li, C. and Krotkov, N. and Yu, H. and Brenot, H. and Van Roozendael, M.},
  title = {Sulfur dioxide vertical column DOAS retrievals from the Ozone Monitoring Instrument: Global observations and comparison to ground-based and satellite data},
  journal = {Journal of Geophysical Research},
  year = {2015},
  volume = {120},
  pages = {2470-2491},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84927695869&doi=10.1002%2f2014JD022657&partnerID=40&md5=fc753ca3bfb6918bb9d0b549218ca7f8},
  doi = {10.1002/2014JD022657}
}
Abstract: Limited availability of ammonia (NH3) observations is currently a barrier for effective monitoring of the nitrogen cycle. It prevents a full understanding of the atmospheric processes in which this trace gas is involved and therefore impedes determining its related budgets. Since the end of 2007, the Infrared Atmospheric Sounding Interferometer (IASI) satellite has been observing NH3 from space at a high spatio-temporal resolution. This valuable data set, already used by models, still needs validation. We present here a first attempt to validate IASI-NH3 measurements using existing independent ground-based and airborne data sets. The yearly distributions reveal similar patterns between ground-based and space-borne observations and highlight the scarcity of local NH3 measurements as well as their spatial heterogeneity and lack of representativity. By comparison with monthly resolved data sets in Europe, China and Africa, we show that IASI-NH3 observations are in fair agreement, but they are characterized by a smaller variation in concentrations. The use of hourly and airborne data sets to compare with IASI individual observations allows investigations of the impact of averaging as well as the representativity of independent observations for the satellite footprint. The importance of considering the latter and the added value of densely located airborne measurements at various altitudes to validate IASI-NH3 columns are discussed. Perspectives and guidelines for future validation work on NH3 satellite observations are presented. © Author(s) 2015.
BibTeX:
@article{VanDammeClarisseDammersEtAl2015,
  author = {Van Damme, M. and Clarisse, L. and Dammers, E. and Liu, X. and Nowak, J.B. and Clerbaux, C. and Flechard, C.R. and Galy-Lacaux, C. and Xu, W. and Neuman, J.A. and Tang, Y.S. and Sutton, M.A. and Erisman, J.W. and Coheur, P.F.},
  title = {Towards validation of ammonia (NH3) measurements from the IASI satellite},
  journal = {Atmospheric Measurement Techniques},
  year = {2015},
  volume = {8},
  pages = {1575-1591},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925853016&doi=10.5194%2famt-8-1575-2015&partnerID=40&md5=27ee1ef096746117a5897f48a33e319f},
  doi = {10.5194/amt-8-1575-2015}
}
Abstract: We exploit 6 years of measurements from the Infrared Atmospheric Sounding Interferometer (IASI)/MetOp-A instrument to identify seasonal patterns and interannual variability of atmospheric NH3. This is achieved by analyzing the time evolution of the monthly mean NH3 columns in 12 subcontinental areas around the world, simultaneously considering measurements from IASI morning and evening overpasses. For most regions, IASI has a sufficient sensitivity throughout the years to capture the seasonal patterns of NH3 columns, and we show that each region is characterized by a well-marked and distinctive cycle, with maxima mainly related to underlying emission processes. The largest column abundances and seasonal amplitudes throughout the years are found in southwestern Asia, with maxima twice as large as what is observed in southeastern China. The relation between emission sources and retrieved NH3 columns is emphasized at a smaller regional scale by inferring a climatology of the month of maximum columns. Key Points Six years of NH3 morning and evening IASI measurements are analyzed Seasonal cycles of atmospheric NH3 are characterized for subcontinental areas Source processes are attributed from a climatology of the month of NH3 maximum © 2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{VanDammeErismanClarisseEtAl2015,
  author = {Van Damme, M. and Erisman, J.W. and Clarisse, L. and Dammers, E. and Whitburn, S. and Clerbaux, C. and Dolman, A.J. and Coheur, P.-F.},
  title = {Worldwide spatiotemporal atmospheric ammonia (NH3) columns variability revealed by satellite},
  journal = {Geophysical Research Letters},
  year = {2015},
  volume = {42},
  pages = {8660-8668},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946615738&doi=10.1002%2f2015GL065496&partnerID=40&md5=955a5abc51b9b3a5fae648c2bb5a80a7},
  doi = {10.1002/2015GL065496}
}
Abstract: Two major droughts in the past decade had large impacts on carbon exchange in the Amazon. Recent analysis of vertical profile measurements of atmospheric CO2 and CO by Gatti et al. (2014) suggests that the 2010 drought turned the normally close-to-neutral annual Amazon carbon balance into a substantial source of nearly 0.5 PgC/yr, revealing a strong drought response. In this study, we revisit this hypothesis and interpret not only the same CO2/CO vertical profile measurements but also additional constraints on carbon exchange such as satellite observations of CO, burned area, and fire hot spots. The results from our CarbonTracker South America data assimilation system suggest that carbon uptake by vegetation was indeed reduced in 2010 but that the magnitude of the decrease strongly depends on the estimated 2010 and 2011 biomass burning emissions. We have used fire products based on burned area (Global Fire Emissions Database version 4), satellite-observed CO columns (Infrared Atmospheric Sounding Interferometer), fire radiative power (Global Fire Assimilation System version 1), and fire hot spots (Fire Inventory from NCAR version 1), and found an increase in biomass burning emissions in 2010 compared to 2011 of 0.16 to 0.24 PgC/yr. We derived a decrease of biospheric uptake ranging from 0.08 to 0.26 PgC/yr, with the range determined from a set of alternative inversions using different biomass burning estimates. Our numerical analysis of the 2010 Amazon drought results in a total reduction of carbon uptake of 0.24 to 0.50 PgC/yr and turns the balance from carbon sink to source. Our findings support the suggestion that the hydrological cycle will be an important driver of future changes in Amazonian carbon exchange. Key Points Amazon carbon budget estimated by CarbonTracker South America Biospheric uptake decreases by 0.08-0.26 PgC/yr in response to 2010 drought Amazon biomass burning emissions more than doubled during 2010 drought ©2015. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{VanDerLaan-LuijkxVanDerVeldeKrolEtAl2015,
  author = {Van Der Laan-Luijkx, I.T. and Van Der Velde, I.R. and Krol, M.C. and Gatti, L.V. and Domingues, L.G. and Correia, C.S.C. and Miller, J.B. and Gloor, M. and Van Leeuwen, T.T. and Kaiser, J.W. and Wiedinmyer, C. and Basu, S. and Clerbaux, C. and Peters, W.},
  title = {Response of the Amazon carbon balance to the 2010 drought derived with CarbonTracker South America},
  journal = {Global Biogeochemical Cycles},
  year = {2015},
  volume = {29},
  pages = {1092-1108},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939137247&doi=10.1002%2f2014GB005082&partnerID=40&md5=42af464e084aa4dd7d0f9289e42fd3a6},
  doi = {10.1002/2014GB005082}
}
Abstract: The Monitoring Atmospheric Composition and Climate (MACC) project represents the European Union's Copernicus Atmosphere Monitoring Service (CAMS) (http://www.copernicus.eu/), which became fully operational during 2015. The global near-real-time MACC model production run for aerosol and reactive gases provides daily analyses and 5-day forecasts of atmospheric composition fields. It is the only assimilation system worldwide that is operational to produce global analyses and forecasts of reactive gases and aerosol fields. We have investigated the ability of the MACC analysis system to simulate tropospheric concentrations of reactive gases covering the period between 2009 and 2012. A validation was performed based on carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3) surface observations from the Global Atmosphere Watch (GAW) network, the O3 surface observations from the European Monitoring and Evaluation Programme (EMEP) and, furthermore, NO2 tropospheric columns, as well as CO total columns, derived from satellite sensors. The MACC system proved capable of reproducing reactive gas concentrations with consistent quality; however, with a seasonally dependent bias compared to surface and satellite observations - for northern hemispheric surface O3 mixing ratios, positive biases appear during the warm seasons and negative biases during the cold parts of the year, with monthly modified normalised mean biases (MNMBs) ranging between -30 and 30 % at the surface. Model biases are likely to result from difficulties in the simulation of vertical mixing at night and deficiencies in the model's dry deposition parameterisation. Observed tropospheric columns of NO2 and CO could be reproduced correctly during the warm seasons, but are mostly underestimated by the model during the cold seasons, when anthropogenic emissions are at their highest level, especially over the US, Europe and Asia. Monthly MNMBs of the satellite data evaluation range from values between -110 and 40 % for NO2 and at most -20 % for CO, over the investigated regions. The underestimation is likely to result from a combination of errors concerning the dry deposition parameterisation and certain limitations in the current emission inventories, together with an insufficiently established seasonality in the emissions. © Author(s) 2015.
BibTeX:
@article{WagnerBlechschmidtBouararEtAl2015,
  author = {Wagner, A. and Blechschmidt, A.-M. and Bouarar, I. and Brunke, E.-G. and Clerbaux, C. and Cupeiro, M. and Cristofanelli, P. and Eskes, H. and Flemming, J. and Flentje, H. and George, M. and Gilge, S. and Hilboll, A. and Inness, A. and Kapsomenakis, J. and Richter, A. and Ries, L. and Spangl, W. and Stein, O. and Weller, R. and Zerefos, C.},
  title = {Evaluation of the MACC operational forecast system - Potential and challenges of global near-real-time modelling with respect to reactive gases in the troposphere},
  journal = {Atmospheric Chemistry and Physics},
  year = {2015},
  volume = {15},
  pages = {14005-14030},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944694829&doi=10.5194%2facp-15-14005-2015&partnerID=40&md5=0276a9dd9d5847d24efc907a3426c0d5},
  doi = {10.5194/acp-15-14005-2015}
}
Abstract: Vegetation fires emit large amounts of nitrogen compounds in the atmosphere, including ammonia (NH3). These emissions are still subject to large uncertainties. In this study, we analyze time series of monthly NH3 total columns (molec cm-2) from the IASI sounder on board MetOp-A satellite and their relation with MODIS fire radiative power (MW) measurements. We derive monthly NH3 emissions estimates for four regions accounting for a major part of the total area affected by fires (two in Africa, one in central South America and one in Southeast Asia), using a simplified box model, and we compare them to the emissions from both the GFEDv3.1 and GFASv1.0 biomass burning emission inventories. In order to strengthen the analysis, we perform a similar comparison for carbon monoxide (CO), also measured by IASI and for which the emission factors used in the inventories to convert biomass burned to trace gas emissions are thought to be more reliable. In general, a good correspondence between NH3 and CO columns and the FRP is found, especially for regions in central South America with correlation coefficients of 0.82 and 0.66, respectively. The comparison with the two biomass burning emission inventories GFASv1.0 and GFEDv3.1 shows good agreements, particularly in the time of the maximum of emissions for the central South America region and in the magnitude for the region of Africa south of the equator. We find evidence of significant non-pyrogenic emissions for the regions of Africa north of the equator (for NH3) and Southeast Asia (for NH3 and CO). On a yearly basis, total emissions calculated from IASI measurements for the four regions reproduce fairly well the interannual variability from the GFEDv3.1 and GFASv1.0 emissions inventories for NH3 but show values about 1.5-2 times higher than emissions given by the two biomass burning emission inventories, even when assuming a fairly long lifetime of 36 h for that species. © 2015 Elsevier Ltd.
BibTeX:
@article{WhitburnVanDammeKaiserEtAl2015,
  author = {Whitburn, S. and Van Damme, M. and Kaiser, J.W. and Van Der Werf, G.R. and Turquety, S. and Hurtmans, D. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F.},
  title = {Ammonia emissions in tropical biomass burning regions: Comparison between satellite-derived emissions and bottom-up fire inventories},
  journal = {Atmospheric Environment},
  year = {2015},
  volume = {121},
  pages = {42-54},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84949110404&doi=10.1016%2fj.atmosenv.2015.03.015&partnerID=40&md5=d3c1a8bb68fca89214be1b54425047e3},
  doi = {10.1016/j.atmosenv.2015.03.015}
}
Abstract: Methanol (CH3OH) is the second most abundant organic compound in the Earth's atmosphere after methane. In this study, we present the first long-term time series of methanol total, lower tropospheric and upper tropospheric-lower stratospheric partial columns derived from the analysis of high resolution Fourier transform infrared solar spectra recorded at the Jungfraujoch station (46.5° N, 3580 m a.s.l.). The retrieval of methanol is very challenging due to strong absorptions of ozone in the region of the selected υ8 band of CH3OH. Two wide spectral intervals have been defined and adjusted in order to maximise the information content. Methanol does not exhibit a significant trend over the 1995-2012 time period, but a strong seasonal modulation characterised by maximum values and variability in June-July, minimum columns in winter and a peak-to-peak amplitude of 130%. Analysis and comparisons with in situ measurements carried out at the Jungfraujoch and ACE-FTS (Atmospheric Chemistry Experiment-Fourier transform spectrometer) occultations have been performed. The total and lower tropospheric columns are also compared with IMAGESv2 model simulations. There is no systematic bias between the observations and IMAGESv2 but the model underestimates the peak-to-peak amplitude of the seasonal modulations.
BibTeX:
@article{BaderStavrakouMullerEtAl2014,
  author = {Bader, W. and Stavrakou, T. and Muller, J.-F. and Reimann, S. and Boone, C.D. and Harrison, J.J. and Flock, O. and Bovy, B. and Franco, B. and Lejeune, B. and Servais, C. and Mahieu, E.},
  title = {Long-term evolution and seasonal modulation of methanol above Jungfraujoch (46.5° N, 8.0° E): Optimisation of the retrieval strategy, comparison with model simulations and independent observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {3861-3872},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911944563&doi=10.5194%2famt-7-3861-2014&partnerID=40&md5=3c143428471a6784d86aa0d0196f67d9},
  doi = {10.5194/amt-7-3861-2014}
}
Abstract: Most satellite models of production have been designed and calibrated for use in the open ocean. Coastal waters are optically more complex, and the use of chlorophyll a (chl a) as a first-order predictor of primary production may lead to substantial errors due to significant quantities of coloured dissolved organic matter (CDOM) and total suspended material (TSM) within the first optical depth. We demonstrate the use of phytoplankton absorption as a proxy to estimate primary production in the coastal waters of the North Sea and Western English Channel for both total, micro- and nano+pico-phytoplankton production. The method is implemented to extrapolate the absorption coefficient of phytoplankton and production at the sea surface to depth to give integrated fields of total and micro- and nano+pico-phytoplankton primary production using the peak in absorption coefficient at red wavelengths. The model is accurate to 8% in the Western English Channel and 22% in this region and the North Sea. By comparison, the accuracy of similar chl a based production models was >250%. The applicability of the method to autonomous optical sensors and remotely sensed aircraft data in both coastal and estuarine environments is discussed. © Inter-Research 2014.
BibTeX:
@article{BarnesTilstoneSmythEtAl2014,
  author = {Barnes, M.K. and Tilstone, G.H. and Smyth, T.J. and Suggett, D.J. and Astoreca, R. and Lancelot, C. and Kromkamp, J.C.},
  title = {Absorption-based algorithm of primary production for total and size-fractionated phytoplankton in coastal waters},
  journal = {Marine Ecology Progress Series},
  year = {2014},
  volume = {504},
  pages = {73-89},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902183113&doi=10.3354%2fmeps10751&partnerID=40&md5=d61084e801a9a3825f6a857515f398e5},
  doi = {10.3354/meps10751}
}
Abstract: We estimate the CO2 flux over Tropical Asia in 2009, 2010, and 2011 using Greenhouse Gases Observing Satellite (GOSAT) total column CO 2(XCO2) and in situ measurements of CO2. Compared to flux estimates from assimilating surface measurements of CO 2, GOSAT XCO2 estimates a more dynamic seasonal cycle and a large source in March-May 2010. The more dynamic seasonal cycle is consistent with earlier work by Patra et al. (2011), and the enhanced 2010 source is supported by independent upper air CO2 measurements from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. Using Infrared Atmospheric Sounding Interferometer (IASI) measurements of total column CO (XCO), we show that biomass burning CO2 can explain neither the dynamic seasonal cycle nor the 2010 source. We conclude that both features must come from the terrestrial biosphere. In particular, the 2010 source points to biosphere response to above-average temperatures that year. Key Points GOSAT estimates a dynamic seasonal cycle over Tropical Asia The GOSAT-estimated seasonal cycle is confirmed by CONTRAIL data IASI CO shows that the dynamism is not caused by biomass burning ©2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BasuKrolButzEtAl2014,
  author = {Basu, S. and Krol, M. and Butz, A. and Clerbaux, C. and Sawa, Y. and Machida, T. and Matsueda, H. and Frankenberg, C. and Hasekamp, O.P. and Aben, I.},
  title = {The seasonal variation of the CO2 flux over Tropical Asia estimated from GOSAT, CONTRAIL, and IASI},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {1809-1815},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84895856326&doi=10.1002%2f2013GL059105&partnerID=40&md5=fa863300699a9e3bb8674508b376364f},
  doi = {10.1002/2013GL059105}
}
Abstract: Norilsk is one of the most polluted cities in the world, largely because of intense mining of heavy metals. Here we present satellite observations of SO2 in a large area surrounding the city, derived from 4 years of measurements from the Infrared Atmospheric Sounding Interferometer (IASI), the nadir thermal infrared (TIR) sounder onboard the MetOp platforms. TIR instruments are conventionally considered to be inadequate for monitoring near-surface composition, because their sensitivity to the lowest part of the atmosphere is limited by the thermal contrast between the ground and the air above it. We demonstrate that IASI is capable of measuring SO2 (here as a partial column from 0 to 2 km) in Norilsk, thanks to the large temperature inversions and the low humidity in wintertime. We discuss the influence of thermal contrast and of surface humidity on the SO2 retrieved columns and estimate the retrieval errors. Using a simple box model, we derive the yearly total emissions of SO2 from Norilsk and compare them to previously reported values. More generally, we present in this work the first large-scale demonstration of the capability of space-based TIR sounders to measure near-surface SO2 anthropogenic pollution. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BauduinClarisseClerbauxEtAl2014,
  author = {Bauduin, S. and Clarisse, L. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {IASI observations of sulfur dioxide (SO2) in the boundary layer of Norilsk},
  journal = {Journal of Geophysical Research},
  year = {2014},
  volume = {119},
  pages = {4253-4263},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84924850713&doi=10.1002%2f2013JD021405&partnerID=40&md5=fcb9601729e9da974d14ca7052db0f7a},
  doi = {10.1002/2013JD021405}
}
Abstract: Forecasting the dispersal of volcanic clouds during an eruption is of primary importance, especially for ensuring aviation safety. As volcanic emissions are characterized by rapid variations of emission rate and height, the (generally) high level of uncertainty in the emission parameters represents a critical issue that limits the robustness of volcanic cloud dispersal forecasts. An inverse modeling scheme, combining satellite observations of the volcanic cloud with a regional chemistry-transport model, allows reconstructing this source term at high temporal resolution. We demonstrate here how a progressive assimilation of freshly acquired satellite observations, via such an inverse modeling procedure, allows for delivering robust sulfur dioxide (SO2) cloud dispersal forecasts during the eruption. This approach provides a computationally cheap estimate of the expected location and mass loading of volcanic clouds, including the identification of SO2-rich parts. Key Points Refined SO2 cloud dispersal forecasts by assimilation of satellite observations Refined estimation of source emissions using an inverse modeling approach Compared to standard methods, cloud SO2-rich parts are robustly forecasted © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BoichuClarisseKhvorostyanovEtAl2014,
  author = {Boichu, M. and Clarisse, L. and Khvorostyanov, D. and Clerbaux, C.},
  title = {Improving volcanic sulfur dioxide cloud dispersal forecasts by progressive assimilation of satellite observations},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {2637-2643},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84899044092&doi=10.1002%2f2014GL059496&partnerID=40&md5=228d9eb28acb13b98bb342d3bcdfde11},
  doi = {10.1002/2014GL059496}
}
Abstract: In this paper we investigate a severe pollution episode that occurred in Beijing, Tianjin, and the Hebei province in January 2013. The episode was caused by the combination of anthropogenic emissions and a high-pressure system that trapped pollutants in the boundary layer. Using IASI (Infrared Atmospheric Sounding Interferometer) satellite measurements, high concentrations of key trace gases such as carbon monoxide (CO), sulfur dioxide (SO2), and ammonia (NH3) along with ammonium sulfate aerosol ((NH 4)2SO4) are found. We show that IASI is able to detect boundary layer pollution in case of large negative thermal contrast combined with high levels of pollution. Our findings demonstrate that anthropogenic key pollutants, such as CO and SO2, can be monitored by IASI in the North China Plain during wintertime in support of air quality evaluation and management. ©2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{BoynardClerbauxClarisseEtAl2014,
  author = {Boynard, A. and Clerbaux, C. and Clarisse, L. and Safieddine, S. and Pommier, M. and Van Damme, M. and Bauduin, S. and Oudot, C. and Hadji-Lazaro, J. and Hurtmans, D. and Coheur, P.-F.},
  title = {First simultaneous space measurements of atmospheric pollutants in the boundary layer from IASI: A case study in the North China Plain},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {645-651},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892466916&doi=10.1002%2f2013GL058333&partnerID=40&md5=b84a0e09a788a64125edf9c690e69aa1},
  doi = {10.1002/2013GL058333}
}
Abstract: Volcanic eruptions emit plumes of ash and gases into the atmosphere, potentially at very high altitudes. Ash-rich plumes are hazardous for airplanes as ash is very abrasive and easily melts inside their engines. With more than 50 active volcanoes per year and the ever-increasing number of commercial flights, the safety of airplanes is a real concern. Satellite measurements are ideal for monitoring global volcanic activity and, in combination with atmospheric dispersion models, to track and forecast volcanic plumes. Here we present the Support to Aviation Control Service (SACS, http://sacs.aeronomie.be), which is a free online service initiated by the European Space Agency (ESA) for the near-real-time (NRT) satellite monitoring of volcanic plumes of SO2 and ash. It combines data from three ultraviolet (UV)-visible and three infrared (IR) spectrometers. The UV-vis sensors are the Ozone Monitoring Instrument (OMI) and the Global Ozone Monitoring Experiment-2 (GOME-2) on-board the two polar orbiting meteorological satellites (MetOp-A & MetOp-B) operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The IR sensors are the Atmospheric InfraRed Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) on-board MetOp-A & MetOp-B. This new multi-sensor warning system of volcanic emissions is based on the selective detection of SO2 and ash. This system is optimised to avoid false alerts while at the same time limiting the number of notifications in case of large plumes. A successful rate with more than 95% of notifications corresponding to true volcanic activity is obtained by the SACS system. copyright © Author(s) 2014.
BibTeX:
@article{BrenotTheysClarisseEtAl2014,
  author = {Brenot, H. and Theys, N. and Clarisse, L. and Van Geffen, J. and Van Gent, J. and Van Roozendael, M. and Van Der A, R. and Hurtmans, D. and Coheur, P.-F. and Clerbaux, C. and Valks, P. and Hedelt, P. and Prata, F. and Rasson, O. and Sievers, K. and Zehner, C.},
  title = {Support to aviation control service (SACS): An online service for near-real-time satellite monitoring of volcanic plumes},
  journal = {Natural Hazards and Earth System Sciences},
  year = {2014},
  volume = {14},
  pages = {1099-1123},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901260246&doi=10.5194%2fnhess-14-1099-2014&partnerID=40&md5=07127ba8a9abca0c9a55a98710d9d4f0},
  doi = {10.5194/nhess-14-1099-2014}
}
Abstract: In the wake of the June 2011 Nabro eruption, large stratospheric plumes were observed by several instruments up to altitudes of 21 km, much higher than initial reported injection heights. It has been debated whether deep convection associated with the Asian Summer Monsoon anticyclone played a vital role in the vertical transport of the plume. Here we present a new and fast SO2 height retrieval algorithm for observations of the Infrared Atmospheric Sounding Interferometer (IASI). A comprehensive validation with forward trajectories and coincident CALIOP measurements is presented which indicates an accuracy better than 2 km for plumes below 20 km and SO2 columns up to the 1 DU level. We use this new product to analyse the Nabro eruption. Our findings indicate an initial plume located mainly between 15 and 17 km for which the lower parts underwent in succession rapid descent and uplift, within the Asian Monsoon anticyclone circulation, up to the stable thermal tropopause between 16 and 18 km, from where it slowly ascended further into the stratosphere. Evidence is presented that emissions in the first week of the eruption also contributed to the stratospheric sulfur input. This includes a second eruption between 15 and 17 km on the 16th and continuous emissions in the mid-troposphere of which some were also entrained and lifted within the anticyclonic circulation. © 2014 Author(s).
BibTeX:
@article{ClarisseCoheurTheysEtAl2014,
  author = {Clarisse, L. and Coheur, P.-F. and Theys, N. and Hurtmans, D. and Clerbaux, C.},
  title = {The 2011 Nabro eruption, a SO2 plume height analysis using IASI measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {3095-3111},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897404216&doi=10.5194%2facp-14-3095-2014&partnerID=40&md5=053c71fd8d158ab7ec0c847859089ccf},
  doi = {10.5194/acp-14-3095-2014}
}
Abstract: This paper interprets tropical tropospheric nitric acid columns from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument with a global chemical transport model (GEOS-Chem). GEOS-Chemand IASI columns generally agree over the tropical ocean to within 10%. However, the GEOS-Chem simulation underestimates IASI nitric acid over Southeast Asia by a factor of 2. The regional nitric acid bias is confirmed by comparing the GEOS-Chem simulation with additional satellite (High Resolution Dynamics Limb Sounder, Atmospheric Chemistry Experiment Fourier Transform Spectrometer) and aircraft (Pacific Exploratory Mission (PEM)-Tropics A and PEM-West B) observations of the middle and upper troposphere. This bias appears to be driven by the lightning NOx parameterization, both in terms of the magnitude of the NOx source and the ozone production efficiency of concentrated lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an ozone production efficiency of 15 mol/mol in lightning plumes over Southeast Asia in conjunction with an additional 0.5 Tg N would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, decreased convective mass flux, or increased scavenging of nitric acid required unrealistic changes to reduce the bias. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{CooperMartinWespesEtAl2014,
  author = {Cooper, M. and Martin, R.V. and Wespes, C. and Coheur, P.-F. and Clerbaux, C. and Murray, L.T.},
  title = {Tropospheric nitric acid columns from the IASI satellite instrument interpreted with a chemical transport model: Implications for parameterizations of nitric oxide production by lightning},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2014},
  volume = {119},
  pages = {10068-10079},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008709551&doi=10.1002%2f2014JD021907&partnerID=40&md5=cabf7069a520a4ced340e56cb705a18e},
  doi = {10.1002/2014JD021907}
}
Abstract: Besides their strong contribution to weather forecast improvement through data assimilation, thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring atmospheric composition changes. The Infrared Atmospheric Sounding Interferometer (IASI) instrument developed by the French space agency (CNES) and launched by EUMETSAT onboard the Metop satellite series is providing essential inputs for weather forecasting and pollution/climate monitoring owing to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance. EUMETSAT is currently preparing the next polar-orbiting program (EPS-SG) with the Metop-SG satellite series that should be launched around 2020. In this framework, CNES is studying the concept of a new instrument, the IASI-New Generation (IASI-NG), characterized by an improvement of both spectral and radiometric characteristics as compared to IASI, with three objectives: (i) continuity of the IASI/Metop series; (ii) improvement of vertical resolution; and (iii) improvement of the accuracy and detection threshold for atmospheric and surface components. In this paper, we show that an improvement of spectral resolution and radiometric noise fulfil these objectives by leading to (i) a better vertical coverage in the lower part of the troposphere, thanks to the increase in spectral resolution; and (ii) an increase in the accuracy of the retrieval of several thermodynamic, climate and chemistry variables, thanks to the improved signal-to-noise ratio as well as less interference between the signatures of the absorbing species in the measured radiances. The detection limit of several atmospheric species is also improved. We conclude that IASI-NG has the potential to strongly benefit the numerical weather prediction, chemistry and climate communities now connected through the European GMES/Copernicus initiative. © Author(s) 2014.
BibTeX:
@article{CrevoisierClerbauxGuidardEtAl2014,
  author = {Crevoisier, C. and Clerbaux, C. and Guidard, V. and Phulpin, T. and Armante, R. and Barret, B. and Camy-Peyret, C. and Chaboureau, J.-P. and Coheur, P.-F. and Crépeau, L. and Dufour, G. and Labonnote, L. and Lavanant, L. and Hadji-Lazaro, J. and Herbin, H. and Jacquinet-Husson, N. and Payan, S. and Péquignot, E. and Pierangelo, C. and Sellitto, P. and Stubenrauch, C.},
  title = {Towards IASI-New Generation (IASI-NG): Impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {4367-4385},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84916604454&doi=10.5194%2famt-7-4367-2014&partnerID=40&md5=6e4606a767925fd89ca62d98f55fb597},
  doi = {10.5194/amt-7-4367-2014}
}
Abstract: Peak stratospheric chlorofluorocarbon (CFC) and other ozone depleting substance (ODS) concentrations were reached in the mid-to late 1990s. Detection and attribution of the expected recovery of the stratospheric ozone layer in an atmosphere with reduced ODSs as well as efforts to understand the evolution of stratospheric ozone in the presence of increasing greenhouse gases are key current research topics. These require a critical examination of the ozone changes with an accurate knowledge of the spatial (geographical and vertical) and temporal ozone response. For such an examination, it is vital that the quality of the measurements used be as high as possible and measurement uncertainties well quantified.

In preparation for the 2014 United Nations Environment Programme (UNEP)/World Meteorological Organization (WMO) Scientific Assessment of Ozone Depletion, the SPARC/IO3C/IGACO-O3/NDACC (SI2N) Initiative was designed to study and document changes in the global ozone profile distribution. This requires assessing long-term ozone profile data sets in regards to measurement stability and uncertainty characteristics. The ultimate goal is to establish suitability for estimating long-term ozone trends to contribute to ozone recovery studies. Some of the data sets have been improved as part of this initiative with updated versions now available.

This summary presents an overview of stratospheric ozone profile measurement data sets (ground and satellite based) available for ozone recovery studies. Here we document measurement techniques, spatial and temporal coverage, vertical resolution, native units and measurement uncertainties. In addition, the latest data versions are briefly described (including data version updates as well as detailing multiple retrievals when available for a given satellite instrument). Archive location information for each data set is also given. © Author(s) 2014.
BibTeX:
@article{HasslerPetropavlovskikhStaehelinEtAl2014,
  author = {Hassler, B. and Petropavlovskikh, I. and Staehelin, J. and August, T. and Bhartia, P.K. and Clerbaux, C. and Degenstein, D. and De Mazière, M. and Dinelli, B.M. and Dudhia, A. and Dufour, G. and Frith, S.M. and Froidevaux, L. and Godin-Beekmann, S. and Granville, J. and Harris, N.R.P. and Hoppel, K. and Hubert, D. and Kasai, Y. and Kurylo, M.J. and Kyrölä, E. and Levelt, P.F. and McElroy, C.T. and McPeters, R.D. and Munro, R. and Nakajima, H. and Parrish, A. and Raspollini, P. and Remsberg, E.E. and Rosenlof, K.H. and Rozanov, A. and Sano, T. and Sasano, Y. and Shiotani, M. and Smit, H.G.J. and Stiller, G. and Tamminen, J. and Tarasick, D.W. and Urban, J. and Van Der A, R.J. and Veefkind, J.P. and Vigouroux, C. and Von Clarmann, T. and Von Savigny, C. and Walker, K.A. and Weber, M. and Wild, J. and Zawodny, J.M.},
  title = {Past changes in the vertical distribution of ozone – Part 1: Measurement techniques, uncertainties and availability},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {1395-1427},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901228705&doi=10.5194%2famt-7-1395-2014&partnerID=40&md5=4682c2083e7b3308725d575e425d857c},
  doi = {10.5194/amt-7-1395-2014}
}
Abstract: Gravity waves are an important driver for the atmospheric circulation and have substantial impact on weather and climate. Satellite instruments offer excellent opportunities to study gravity waves on a global scale. This study focuses on observations from the Atmospheric Infrared Sounder (AIRS) onboard the National Aeronautics and Space Administration Aqua satellite and the Infrared Atmospheric Sounding Interferometer (IASI) onboard the European MetOp satellites. The main aim of this study is an intercomparison of stratospheric gravity wave observations of both instruments. In particular, we analyzed AIRS and IASI 4.3 μm brightness temperature measurements, which directly relate to stratospheric temperature. Three case studies showed that AIRS and IASI provide a clear and consistent picture of the temporal development of individual gravity wave events. Statistical comparisons based on a 5-year period of measurements (2008-2012) showed similar spatial and temporal patterns of gravity wave activity. However, the statistical comparisons also revealed systematic differences of variances between AIRS and IASI that we attribute to the different spatial measurement characteristics of both instruments. We also found differences between day- and nighttime data that are partly due to the local time variations of the gravity wave sources. While AIRS has been used successfully in many previous gravity wave studies, IASI data are applied here for the first time for that purpose. Our study shows that gravity wave observations from different hyperspectral infrared sounders such as AIRS and IASI can be directly related to each other, if instrument-specific characteristics such as different noise levels and spatial resolution and sampling are carefully considered. The ability to combine observations from different satellites provides an opportunity to create a long-term record, which is an exciting prospect for future climatological studies of stratospheric gravity wave activity. © Author(s) 2014.
BibTeX:
@article{HoffmannAlexanderClerbauxEtAl2014,
  author = {Hoffmann, L. and Alexander, M.J. and Clerbaux, C. and Grimsdell, A.W. and Meyer, C.I. and Rößler, T. and Tournier, B.},
  title = {Intercomparison of stratospheric gravity wave observations with AIRS and IASI},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {4517-4537},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84919608580&doi=10.5194%2famt-7-4517-2014&partnerID=40&md5=a86b2db51649ed6837f71d4c6a647741},
  doi = {10.5194/amt-7-4517-2014}
}
Abstract: A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. CO2emissions are assessed by means of an emission model assuming a direct relationship between the biomass burning rate (BBR) and the fire radiative power (FRP) derived from MODIS measurements. The key features of the method are (1) estimating the FRP-to-BBR conversion factors (α) for different vegetative land cover types by assimilating the satellite observations of co-emitted species into the CTM, (2) optimal combination of the estimates of α derived independently from satellite observations of different species (CO and aerosol in this study), and (3) estimation of the diurnal cycle of the fire emissions directly from the FRP measurements. Values of α for forest and grassland fires in Siberia and their uncertainties are estimated using the Infrared Atmospheric Sounding Interferometer (IASI) carbon monoxide (CO) retrievals and MODIS aerosol optical depth (AOD) measurements combined with outputs from the CHIMERE mesoscale chemistry-transport model. The constrained CO emissions are validated through comparison of the respective simulations with independent data of ground-based CO measurements at the ZOTTO site. Using our optimal regional-scale estimates of the conversion factors (which are found to be in agreement with earlier published estimates obtained from local measurements of experimental fires), the total CO2emissions from wildfires in Siberia in 2012 are estimated to be in the range from 280 to 550 Tg C, with the optimal (maximum likelihood) value of 392 Tg C. Sensitivity test cases featuring different assumptions regarding the injection height and diurnal variations of emissions indicate that the derived estimates of the total CO2emissions in Siberia are robust with respect to the modeling options (the different estimates vary within less than 15% of their magnitude). The CO2emission estimates obtained for several years are compared with independent estimates provided by the GFED3.1 and GFASv1.0 global emission inventories. It is found that our "top-down" estimates for the total annual biomass burning CO2emissions in the period from 2007 to 2011 in Siberia are by factors of 2.5 and 1.8 larger than the respective bottom-up estimates; these discrepancies cannot be fully explained by uncertainties in our estimates. There are also considerable differences in the spatial distribution of the different emission estimates; some of those differences have a systematic character and require further analysis. © Author(s) 2014. CC Attribution 3.0 License.
BibTeX:
@article{KonovalovBerezinCiaisEtAl2014,
  author = {Konovalov, I.B. and Berezin, E.V. and Ciais, P. and Broquet, G. and Beekmann, M. and Hadji-Lazaro, J. and Clerbaux, C. and Andreae, M.O. and Kaiser, J.W. and Schulze, E.-D.},
  title = {Constraining CO2emissions from open biomass burning by satellite observations of co-emitted species: A method and its application to wildfires in Siberia},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {10383-10410},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907486608&doi=10.5194%2facp-14-10383-2014&partnerID=40&md5=9e53deff0bf36f107f6e431634fe565a},
  doi = {10.5194/acp-14-10383-2014}
}
Abstract: The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards, was introduced after the eruption of the Icelandic volcano Eyjafjallajökull in the spring of 2010 to facilitate the development of an optimal End­to­End System for Volcanic Ash Plume Monitoring and Prediction. The Eyjafjallajökull plume drifted towards Europe and caused major disruptions of European air traffic for several weeks affecting the everyday life of millions of people. The limitations in volcanic plume monitoring and prediction capabilities gave birth to this observational system which is based on comprehensive satellite­derived ash plume and sulphur dioxide [SO2] level estimates, as well as a widespread validation using supplementary satellite, aircraft and ground­based measurements. Inter­comparison of the volcanic total SO2 column and plume height observed by GOME­2/Metop­A and IASI/Metop­A are shown before, during and after the Eyjafjallajökull 2010 eruptions as well as for the 2011 Grímsvötn eruption. Co­located ground­based Brewer Spectro­photometer data extracted from the World Ozone and Ultraviolet Radiation Data Centre for de Bilt, the Netherlands, are also compared to the different satellite estimates. Promising agreement is found for the two different types of instrument for the SO2 columns with linear regression coefficients ranging around from 0.64 when comparing the different instruments and 0.85 when comparing the two different IASI algorithms. The agreement for the plume height is lower, possibly due to the major differences between the height retrieval part of the GOME2 and IASI algorithms. The comparisons with the Brewer ground­based station in de Bilt, The Netherlands show good qualitative agreement for the peak of the event however stronger eruptive signals are required for a longer quantitative comparison. © 2014, Editrice Compositori s.r.l., All rights reserved.
BibTeX:
@article{KoukouliClarisseCarboniEtAl2014,
  author = {Koukouli, M.E. and Clarisse, L. and Carboni, E. and Van Gent, J. and Spinetti, C. and Balis, D. and Dimopoulos, S. and Grainger, R. and Theys, N. and Tampellini, L. and Zehner, C.},
  title = {Intercomparison of Metop-A SO2 measurements during the 2010- 2011 Icelandic eruptions},
  journal = {Annals of Geophysics},
  year = {2014},
  volume = {57},
  article number = {A007},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940857581&doi=10.4401%2fag-6613&partnerID=40&md5=541c0d30c78d613c827105151a3a9b14},
  doi = {10.4401/ag-6613}
}
Abstract: We present the results of an extensive validation program of the most recent version of ozone vertical profiles retrieved with the IMK/IAA (Institute for Meteorology and Climate Research/Instituto de Astrofísica de Andalucía) MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) research level 2 processor from version 5 spectral level 1 data. The time period covered corresponds to the reduced spectral resolution period of the MIPAS instrument, i.e., January 2005-April 2012. The comparison with satellite instruments includes all post-2005 satellite limb and occultation sensors that have measured the vertical profiles of tropospheric and stratospheric ozone: ACE-FTS, GOMOS, HALOE, HIRDLS, MLS, OSIRIS, POAM, SAGE II, SCIAMACHY, SMILES, and SMR. In addition, balloon-borne MkIV solar occultation measurements and ground-based Umkehr measurements have been included, as well as two nadir sensors: IASI and SBUV. For each reference data set, bias determination and precision assessment are performed. Better agreement with reference instruments than for the previous data version, V5R-O3-220 (Laeng et al., 2014), is found: the known high bias around the ozone vmr (volume mixing ratio) peak is significantly reduced and the vertical resolution at 35 km has been improved. The agreement with limb and solar occultation reference instruments that have a known small bias vs. ozonesondes is within 7% in the lower and middle stratosphere and 5% in the upper troposphere. Around the ozone vmr peak, the agreement with most of the satellite reference instruments is within 5%; this bias is as low as 3% for ACE-FTS, MLS, OSIRIS, POAM and SBUV. © Author(s) 2014.
BibTeX:
@article{LaengGrabowskiVonClarmannEtAl2014,
  author = {Laeng, A. and Grabowski, U. and Von Clarmann, T. and Stiller, G. and Glatthor, N. and Höpfner, M. and Kellmann, S. and Kiefer, M. and Linden, A. and Lossow, S. and Sofieva, V. and Petropavlovskikh, I. and Hubert, D. and Bathgate, T. and Bernath, P. and Boone, C.D. and Clerbaux, C. and Coheur, P. and Damadeo, R. and Degenstein, D. and Frith, S. and Froidevaux, L. and Gille, J. and Hoppel, K. and Mchugh, M. and Kasai, Y. and Lumpe, J. and Rahpoe, N. and Toon, G. and Sano, T. and Suzuki, M. and Tamminen, J. and Urban, J. and Walker, K. and Weber, M. and Zawodny, J.},
  title = {Validation of MIPAS IMK/IAA V5R-O3-224 ozone profiles},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {3971-3987},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84913585537&doi=10.5194%2famt-7-3971-2014&partnerID=40&md5=90ab826e882aa3fa05994a2361118c4b},
  doi = {10.5194/amt-7-3971-2014}
}
Abstract: The abundance of chlorine in the Earth's atmosphere increased considerably during the 1970s to 1990s, following large emissions of anthropogenic long-lived chlorine-containing source gases, notably the chlorofluorocarbons. The chemical inertness of chlorofluorocarbons allows their transport and mixing throughout the troposphere on a global scale, before they reach the stratosphere where they release chlorine atoms that cause ozone depletion. The large ozone loss over Antarctica was the key observation that stimulated the definition and signing in 1987 of the Montreal Protocol, an international treaty establishing a schedule to reduce the production of the major chlorine- and bromine-containing halocarbons. Owing to its implementation, the near-surface total chlorine concentration showed a maximum in 1993, followed by a decrease of half a per cent to one per cent per year, in line with expectations. Remote-sensing data have revealed a peak in stratospheric chlorine after 1996, then a decrease of close to one per cent per year, in agreement with the surface observations of the chlorine source gases and model calculations. Here we present ground-based and satellite data that show a recent and significant increase, at the 2σ level, in hydrogen chloride (HCl), the main stratospheric chlorine reservoir, starting around 2007 in the lower stratosphere of the Northern Hemisphere, in contrast with the ongoing monotonic decrease of near-surface source gases. Using model simulations, we attribute this trend anomaly to a slowdown in the Northern Hemisphere atmospheric circulation, occurring over several consecutive years, transporting more aged air to the lower stratosphere, and characterized by a larger relative conversion of source gases to HCl. This short-term dynamical variability will also affect other stratospheric tracers and needs to be accounted for when studying the evolution of the stratospheric ozone layer. ©2014 Macmillan Publishers Limited. All rights reserved.
BibTeX:
@article{MahieuChipperfieldNotholtEtAl2014,
  author = {Mahieu, E. and Chipperfield, M.P. and Notholt, J. and Reddmann, T. and Anderson, J. and Bernath, P.F. and Blumenstock, T. and Coffey, M.T. and Dhomse, S.S. and Feng, W. and Franco, B. and Froidevaux, L. and Griffith, D.W.T. and Hannigan, J.W. and Hase, F. and Hossaini, R. and Jones, N.B. and Morino, I. and Murata, I. and Nakajima, H. and Palm, M. and Paton-Walsh, C. and Russell, J.M., III and Schneider, M. and Servais, C. and Smale, D. and Walker, K.A.},
  title = {Recent Northern Hemisphere stratospheric HCl increase due to atmospheric circulation changes},
  journal = {Nature},
  year = {2014},
  volume = {515},
  pages = {104-107},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920716956&doi=10.1038%2fnature13857&partnerID=40&md5=0208eb20f578c338c5eb1d24ef1023be},
  doi = {10.1038/nature13857}
}
Abstract: The advent of high-resolution spectrographs and detailed stellar atmosphere modelling has strengthened the need for accurate molecular data. Carbon-enhanced metal-poor (CEMP) stars spectra are interesting objects with which to study transitions from the CH molecule. We combine programs for spectral analysis of molecules and stellar-radiative transfer codes to build an extensive CH linelist, including predissociation broadening as well as newly identified levels. We show examples of strong predissociation CH lines in CEMP stars, and we stress the important role played by the CH features in the Bond-Neff feature depressing the spectra of barium stars by as much as 0.2 mag in the λ = 3000-5500 Å range. Because of the extreme thermodynamic conditions prevailing in stellar atmospheres (compared to the laboratory), molecular transitions with high energy levels can be observed. Stellar spectra can thus be used to constrain and improve molecular data. © 2014 ESO.
BibTeX:
@article{MasseronPlezVanEckEtAl2014,
  author = {Masseron, T. and Plez, B. and Van Eck, S. and Colin, R. and Daoutidis, I. and Godefroid, M. and Coheur, P.-F. and Bernath, P. and Jorissen, A. and Christlieb, N.},
  title = {CH in stellar atmospheres: An extensive linelist},
  journal = {Astronomy and Astrophysics},
  year = {2014},
  volume = {571},
  article number = {A47},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908669914&doi=10.1051%2f0004-6361%2f201423956&partnerID=40&md5=c4ec4fd1543d9ed0b407eca651fa7212},
  doi = {10.1051/0004-6361/201423956}
}
Abstract: Modeling the transport of volcanic ash and gases released during volcanic eruptions is crucially dependent on knowledge of the source term of the eruption, that is, the source strength as a function of altitude and time. For the first time, an inversion method is used to estimate the source terms of both volcanic sulfur dioxide (SO2) and ash. It was applied to the explosive volcanic eruption of Grímsvötn, Iceland, in May 2011. The method uses input from the particle dispersion model, FLEXPART (flexible particle dispersion model), a priori source estimates, and satellite observations of SO2 or ash total columns from Infrared Atmospheric Sounding Interferometer to separately obtain the source terms for volcanic SO2 and fine ash. The estimated source terms show that SO2 was emitted mostly to high altitudes (5 to 13 km) during about 18 h (22 May, 00-18 UTC) while fine ash was emitted mostly to low altitudes (below 4 km) during roughly 24 h (22 May 06 UTC to 23 May 06 UTC). FLEXPART simulations using the estimated source terms show a clear separation of SO2 (transported mostly northwestward) and the fine ash (transported mostly southeastward). This corresponds well with independent satellite observations and measured aerosol mass concentrations and lidar measurements at surface stations in Scandinavia. Aircraft measurements above Iceland and Germany confirmed that the ash was located in the lower atmosphere. This demonstrates that the inversion method, in this case, is able to distinguish between emission heights of SO2 and ash and can capture resulting differences in transport patterns. Key Points Ash and SO2 source terms estimated using inverse techniques and satellite data The transport and separation of ash and SO2 are modeled Model simulations correspond well with a range of independent observations ©2014. The Authors.
BibTeX:
@article{MoxnesKristiansenStohlEtAl2014,
  author = {Moxnes, E.D. and Kristiansen, N.I. and Stohl, A. and Clarisse, L. and Durant, A. and Weber, K. and Vogel, A.},
  title = {Separation of ash and sulfur dioxide during the 2011 Grímsvötn eruption},
  journal = {Journal of Geophysical Research: Atmospheres},
  year = {2014},
  volume = {119},
  pages = {7477-7501},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84904719277&doi=10.1002%2f2013JD021129&partnerID=40&md5=185aa3c7e4811e5f42ced9ca70991e55},
  doi = {10.1002/2013JD021129}
}
Abstract: We apply the Tropospheric Emission Spectrometer (TES) ozone retrieval algorithm to Infrared Atmospheric Sounding Instrument (IASI) radiances and characterise the uncertainties and information content of the retrieved ozone profiles. This study focuses on mid-latitudes for the year 2008. We validate our results by comparing the IASI ozone profiles to ozone sondes. In the sonde comparisons, we find a negative bias (1-10%) in the IASI profiles in the lower to mid-troposphere and a positive bias (up to 14%) in the upper troposphere/lower stratosphere (UTLS) region. For the described cases, the degrees of freedom for signal are on average 3.2, 0.3, 0.8, and 0.9 for the columns 0 km - top of atmosphere, (0-6), (0-11), and (8-16) km, respectively. We find that our biases with respect to sondes and our degrees of freedom for signal for ozone are comparable to previously published results from other IASI ozone algorithms. In addition to evaluating biases, we validate the retrieval errors by comparing predicted errors to the sample covariance matrix of the IASI observations themselves. For the predicted versus empirical error comparison, we find that these errors are consistent and that the measurement noise and the interference of temperature and water vapour on the retrieval together mostly explain the empirically derived random errors. In general, the precision of the IASI ozone profiles is better than 20%. © 2014 Author(s).
BibTeX:
@article{OetjenPayneKulawikEtAl2014,
  author = {Oetjen, H. and Payne, V.H. and Kulawik, S.S. and Eldering, A. and Worden, J. and Edwards, D.P. and Francis, G.L. and Worden, H.M. and Clerbaux, C. and Hadji-Lazaro, J. and Hurtmans, D.},
  title = {Extending the satellite data record of tropospheric ozone profiles from Aura-TES to MetOp-IASI: Characterisation of optimal estimation retrievals},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {4223-4236},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84915791193&doi=10.5194%2famt-7-4223-2014&partnerID=40&md5=417429cefaafe9c908aa9e74d2a07df6},
  doi = {10.5194/amt-7-4223-2014}
}
Abstract: This study presents the joint H2 16O and HDO retrieval from Infrared Atmospheric Sounding Interferometer (IASI) spectra over western Siberia. IASI is an instrument on board the MetOp-A European satellite. The global coverage of the instrument and the good signal-to-noise ratio allow us to provide information on δD over this remote region. We show that IASI measurements may be used to estimate integrated δD between the surface and 3 km altitude or from 1 to 5 km depending on the thermal contrast, with observational errors lower than 4% and 7 %, respectively. The retrieved data are compared to simulations from an isotopic general circulation model, LMDZ-iso for 2011. The satellite measurements and the model agree well and they reproduce well the seasonal and day-to-day variations for δD, presenting a good correlation (r up to 0.8 with the smoothed data in summer). The IASI-based retrievals also show the seasonal variation of the specific humidity in both altitude ranges. © Author(s) 2014.
BibTeX:
@article{PommierLacourRisiEtAl2014,
  author = {Pommier, M. and Lacour, J.-L. and Risi, C. and Bréon, F.M. and Clerbaux, C. and Coheur, P.-F. and Gribanov, K. and Hurtmans, D. and Jouzel, J. and Zakharov, V.},
  title = {Observation of tropospheric δd by IASI over western Siberia: Comparison with a general circulation model},
  journal = {Atmospheric Measurement Techniques},
  year = {2014},
  volume = {7},
  pages = {1581-1595},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907260770&doi=10.5194%2famt-7-1581-2014&partnerID=40&md5=8ed05b4c8d05ff9c77aad13558552ae6},
  doi = {10.5194/amt-7-1581-2014}
}
Abstract: Over the Mediterranean region, elevated tropospheric ozone (O3) values are recorded, especially in summer. We use the thermal Infrared Atmospheric Sounding Interferometer (IASI) and the Weather Research and Forecasting Model with Chemistry (WRF-Chem) to understand and interpret the factors and emission sources responsible for the high O3concentrations observed in the Mediterranean troposphere. Six years (2008-2013) of IASI data have been analyzed and results show consistent maxima during summer, with an increase of up to 22% in the [0-8] km O3column in the eastern part of the basin compared to the middle of the basin. We focus on summer 2010 to investigate the processes that contribute to these summer maxima. Using two modeled O3tracers (inflow to the model domain and local anthropogenic emissions), we show that, between the surface and 2 km, O3is mostly formed from anthropogenic emissions, while above 4 km it is mostly transported from outside the domain or from stratospheric origins. Evidence of stratosphere-to-troposphere exchange (STE) events in the eastern part of the basin is shown, and corresponds to a low water vapor mixing ratio and high potential vorticity. © 2014 Author(s).
BibTeX:
@article{SafieddineBoynardCoheurEtAl2014,
  author = {Safieddine, S. and Boynard, A. and Coheur, P.-F. and Hurtmans, D. and Pfister, G. and Quennehen, B. and Thomas, J.L. and Raut, J.-C. and Law, K.S. and Klimont, Z. and Hadji-Lazaro, J. and George, M. and Clerbaux, C.},
  title = {Summertime tropospheric ozone assessment over the Mediterranean region using the thermal infrared IASI/MetOp sounder and the WRF-Chem model},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {10119-10131},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907918397&doi=10.5194%2facp-14-10119-2014&partnerID=40&md5=c882337d9201387f60bac24384e04df2},
  doi = {10.5194/acp-14-10119-2014}
}
Abstract: Mt. Etna volcano in Italy is one of the most active degassing volcanoes worldwide, emitting a mean of 1.7 Mt/year of Sulphur Dioxide (SO2) in quiescent periods. In this work, SO2 measurements retrieved by Moderate Resolution Imaging Spectroradiometer (MODIS), hyper-spectral Infrared Atmospheric Sounding Interferometer (IASI) and the second Global Ozone Monitoring Experiment (GOME-2) data are compared with the ground-based data from the FLux Automatic MEasurement monitoring network (FLAME). Among the eighteen lava fountain episodes occurring at Mt. Etna in 2011, the 10 April paroxysmal event has been selected as a case-study for the simultaneous observation of the SO2 cloud by satellite and ground-based sensors. For each data-set two retrieval techniques were adopted and the measurements of SO2 mass and flux with their respective uncertainty were obtained. With respect to the FLAME SO2 mass of 4.5 Gg, MODIS, IASI and GOME-2 differ by about 10%, 15% and 30%, respectively. The SO2 flux correlation coefficient between MODIS and FLAME is 0.84. All the retrievals within the respective errors are in agreement with the ground-based measurements supporting the validity of these space measurements. © 2014, Editrice Compositori s.r.l. All rights reserved.
BibTeX:
@article{SpinettiSalernoCaltabianoEtAl2014,
  author = {Spinetti, C. and Salerno, G.G. and Caltabiano, T. and Carboni, E. and Clarisse, L. and Corradini, S. and Grainger, R.G. and Hedelt, P.A. and Koukouli, M.E. and Merucci, L. and Siddans, R. and Tampellini, L. and Theys, N. and Valks, P. and Zehner, C.},
  title = {Volcanic SO2 by UV-TIR satellite retrievals: Validation by using ground-based network at Mt. Etna},
  journal = {Annals of Geophysics},
  year = {2014},
  volume = {57},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940882368&doi=10.4401%2fag-6641&partnerID=40&md5=e4ad45df2d0a7ace4f9f75e9a980caed},
  doi = {10.4401/ag-6641}
}
Abstract: Despite the developments in the global modelling of chemistry and of the parameterization of the physical processes, carbon monoxide (CO) concentrations remain underestimated during Northern Hemisphere (NH) winter by most state-of-the-art chemistry transport models. The consequential model bias can in principle originate from either an underestimation of CO sources or an overestimation of its sinks. We address both the role of surface sources and sinks with a series of MOZART (Model for Ozone And Related Tracers) model sensitivity studies for the year 2008 and compare our results to observational data from ground-based stations, satellite observations, and vertical profiles from measurements on passenger aircraft. In our base case simulation using MACCity (Monitoring Atmospheric Composition and Climate project) anthropogenic emissions, the near-surface CO mixing ratios are underestimated in the Northern Hemisphere by more than 20 ppb from December to April, with the largest bias of up to 75 ppb over Europe in January. An increase in global biomass burning or biogenic emissions of CO or volatile organic compounds (VOCs) is not able to reduce the annual course of the model bias and yields concentrations over the Southern Hemisphere which are too high. Raising global annual anthropogenic emissions with a simple scaling factor results in overestimations of surface mixing ratios in most regions all year round. Instead, our results indicate that anthropogenic CO and, possibly, VOC emissions in the MACCity inventory are too low for the industrialized countries only during winter and spring. Reasonable agreement with observations can only be achieved if the CO emissions are adjusted seasonally with regionally varying scaling factors. A part of the model bias could also be eliminated by exchanging the original resistance-type dry deposition scheme with a parameterization for CO uptake by oxidation from soil bacteria and microbes, which reduces the boreal winter dry deposition fluxes. The best match to surface observations, satellite retrievals, and aircraft observations was achieved when the modified dry deposition scheme was combined with increased wintertime road traffic emissions over Europe and North America (factors up to 4.5 and 2, respectively). One reason for the apparent underestimation of emissions may be an exaggerated downward trend in the Representative Concentration Pathway (RCP) 8.5 scenario in these regions between 2000 and 2010, as this scenario was used to extrapolate the MACCity emissions from their base year 2000. This factor is potentially amplified by a lack of knowledge about the seasonality of emissions. A methane lifetime of 9.7 yr for our basic model and 9.8 yr for the optimized simulation agrees well with current estimates of global OH, but we cannot fully exclude a potential effect from errors in the geographical and seasonal distribution of OH concentrations on the modelled CO. © Author(s) 2014. CC Attribution 3.0 License.
BibTeX:
@article{SteinSchultzBouararEtAl2014,
  author = {Stein, O. and Schultz, M.G. and Bouarar, I. and Clark, H. and Huijnen, V. and Gaudel, A. and George, M. and Clerbaux, C.},
  title = {On the wintertime low bias of Northern Hemisphere carbon monoxide found in global model simulations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {9295-9316},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907021448&doi=10.5194%2facp-14-9295-2014&partnerID=40&md5=2eb46f0cea1d22ca2513a26ee87e6481},
  doi = {10.5194/acp-14-9295-2014}
}
Abstract: Volcanoes release large amounts of halogen species such as HCl and HBr, which can be converted into reactive halogens by heterogeneous photochemical reactions that are currently not fully characterized. Here we report on the first satellite detection of volcanic chlorine dioxide (OClO). Measurements were performed using the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography instrument for the ash-laden plume emitted after the 2011 eruption of Puyehue-Cordõn Caulle in Chile. We also identified volcanic BrO using the Ozone Monitoring Instrument, as well as enhanced HCl in data of the Microwave Limb Sounder instrument. These observations suggest that OClO was formed in the plume by the ClO + BrO reaction in presence of a large excess of ClO. The present satellite data set could help better understand reactive halogen chemistry in volcanic plumes and its impact on atmospheric composition. ©2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{TheysDeSmedtVanRoozendaelEtAl2014,
  author = {Theys, N. and De Smedt, I. and Van Roozendael, M. and Froidevaux, L. and Clarisse, L. and Hendrick, F.},
  title = {First satellite detection of volcanic OClO after the eruption of Puyehue-Cordõn Caulle},
  journal = {Geophysical Research Letters},
  year = {2014},
  volume = {41},
  pages = {667-672},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892698897&doi=10.1002%2f2013GL058416&partnerID=40&md5=5bb102635a22d51e140a5cc69acddbe0},
  doi = {10.1002/2013GL058416}
}
Abstract: Ammonia (NH3) emissions in the atmosphere have increased substantially over the past decades, largely because of intensive livestock production and use of fertilizers. As a short-lived species, NH3 is highly variable in the atmosphere and its concentration is generally small, except near local sources. While ground-based measurements are possible, they are challenging and sparse. Advanced infrared sounders in orbit have recently demonstrated their capability to measure NH3, offering a new tool to refine global and regional budgets. In this paper we describe an improved retrieval scheme of NH3 total columns from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI). It exploits the hyperspectral character of this instrument by using an extended spectral range (800-1200 cm-1) where NH3 is optically active. This scheme consists of the calculation of a dimensionless spectral index from the IASI level1C radiances, which is subsequently converted to a total NH3 column using look-up tables built from forward radiative transfer model simulations. We show how to retrieve the NH3 total columns from IASI quasi-globally and twice daily above both land and sea without large computational resources and with an improved detection limit. The retrieval also includes error characterization of the retrieved columns. Five years of IASI measurements (1 November 2007 to 31 October 2012) have been processed to acquire the first global and multiple-year data set of NH3 total columns, which are evaluated and compared to similar products from other retrieval methods. Spatial distributions from the five years data set are provided and analyzed at global and regional scales. In particular, we show the ability of this method to identify smaller emission sources than those previously reported, as well as transport patterns over the ocean. The five-year time series is further examined in terms of seasonality and interannual variability (in particular as a function of fire activity) separately for the Northern and Southern Hemispheres. © Author(s) 2014.
BibTeX:
@article{VanDammeClarisseHealdEtAl2014,
  author = {Van Damme, M. and Clarisse, L. and Heald, C.L. and Hurtmans, D. and Ngadi, Y. and Clerbaux, C. and Dolman, A.J. and Erisman, J.W. and Coheur, P.F.},
  title = {Global distributions, time series and error characterization of atmospheric ammonia (NH3) from IASI satellite observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2014},
  volume = {14},
  pages = {2905-2922},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897888799&doi=10.5194%2facp-14-2905-2014&partnerID=40&md5=268e3eb2830bb75ee3a708ad8d74d60a},
  doi = {10.5194/acp-14-2905-2014}
}
Abstract: Monitoring ammonia (NH3) concentrations on a global to regional scale is a challenge. Due to the limited availability of reliable ground-based measurements, the determination of NH3 distributions generally relies on model calculations. Novel remotely sensed NH3 burdens provide valuable insights to complement traditional assessments for clear-sky conditions. This paper presents a first quantitative comparison between Atmospheric Sounding Interferometer (IASI) satellite observations and LOTOS-EUROS model results over Europe and Western Russia. A methodology to account for the variable retrieval sensitivity of the measurements is described. Four years of data (2008–2011) highlight three main agricultural hot spot areas in Europe: the Po Valley, the continental part of Northwestern Europe, and the Ebro Valley. The spatial comparison reveals a good overall agreement of the NH3 distributions not only in these source regions but also over remote areas and over sea when transport is observed. On average, the measured columns exceed the modeled ones, except for a few cases. Large discrepancies over several industrial areas in Eastern Europe and Russia point to underestimated emissions in the underlying inventories. The temporal analysis over the three hot spot areas reveals that the seasonality is well captured by the model when the lower sensitivity of the satellite measurements in the colder months is taken into account. Comparison of the daily time series indicates possible misrepresentations of the timing and magnitude of the emissions. Finally, specific attention to biomass burning events shows that modeled plumes are less spread out than the observed ones. This is confirmed for the 2010 Russian fires with a comparison using in situ observations. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{VanDammeWichinkKruitSchaapEtAl2014,
  author = {Van Damme, M. and Wichink Kruit, R.J. and Schaap, M. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Dammers, E. and Dolman, A.J. and Erisman, J.W.},
  title = {Evaluating 4 years of atmospheric ammonia (NH3) over Europe using IASI satellite observations and LOTOS-EUROS model results},
  journal = {Journal of Geophysical Research},
  year = {2014},
  volume = {119},
  pages = {9549-9566},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906675715&doi=10.1002%2f2014JD021911&partnerID=40&md5=4597ee44f3f4ae44b61cb614ed8b1686},
  doi = {10.1002/2014JD021911}
}
Abstract: Relying on high-resolution Fourier transform infrared (FTIR) spectra, the present work involved extensive measurements of individual line intensities and self-broadening coefficients for the ν7 band of 12C2H4. The measured self-broadening coefficients exhibit a dependence on both J and Ka. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database, the measured line intensities were found to be higher by about 10% for high J lines in the P branch and lower by about 5% for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. The impact of the presently measured line intensities on retrievals of atmospheric ethylene in the 949.0-952.0cm-1 microwindow was evaluated using a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The use of HITRAN 2012 with line intensities modified to match the present measurements led to a systematic reduction of the measured total columns of ethylene by -4.1 ± 0.1 %. © 2014 Elsevier Ltd.
BibTeX:
@article{VanderAuweraFaytTudorieEtAl2014,
  author = {Vander Auwera, J. and Fayt, A. and Tudorie, M. and Rotger, M. and Boudon, V. and Franco, B. and Mahieu, E.},
  title = {Self-broadening coefficients and improved line intensities for the ν7 band of ethylene near 10.5 μm, and impact on ethylene retrievals from Jungfraujoch solar spectra},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2014},
  volume = {148},
  pages = {177-185},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905222358&doi=10.1016%2fj.jqsrt.2014.07.003&partnerID=40&md5=5dbeb9cdbcf38d74909c4289625673f1},
  doi = {10.1016/j.jqsrt.2014.07.003}
}
Abstract: Depending on the magnitude of their eruptions, volcanoes impact the atmosphere at various temporal and spatial scales. The volcanic source remains a major unknown to rigorously assess these impacts. At the scale of an eruption, the limited knowledge of source parameters, including time variations of erupted mass flux and emission profile, currently represents the greatest issue that limits the reliability of volcanic cloud forecasts. Today, a growing number of satellite and remote sensing observations of distant plumes are becoming available, bringing indirect information on these source terms. Here, we develop an inverse modelling approach combining satellite observations of the volcanic plume with an Eulerian regional chemistry-transport model (CHIMERE) to characterise the volcanic SO2 emissions during an eruptive crisis. The May 2010 eruption of Eyjafjallajökull is a perfect case study to apply this method as the volcano emitted substantial amounts of SO2 during more than a month. We take advantage of the SO2 column amounts provided by a vast set of IASI (Infrared Atmospheric Sounding Interferometer) satellite images to reconstruct retrospectively the time series of the mid-tropospheric SO2 flux emitted by the volcano with a temporal resolution of ∼2 h, spanning the period from 1 to 12 May 2010. We show that no a priori knowledge on the SO2 flux is required for this reconstruction. The initialisation of chemistry-transport modelling with this reconstructed source allows for reliable simulation of the evolution of the long-lived tropospheric SO2 cloud over thousands of kilometres. Heterogeneities within the plume, which mainly result from the temporal variability of the emissions, are correctly tracked over a timescale of a week. The robustness of our approach is also demonstrated by the broad similarities between the SO2 flux history determined by this study and the ash discharge behaviour estimated by other means during the phases of high explosive activity at Eyjafjallajö kull in May 2010. Finally, we show how a sequential IASI data assimilation allows for a substantial improvement in the forecasts of the location and concentration of the plume compared to an approach assuming constant flux at the source. As the SO2 flux is an important indicator of the volcanic activity, this approach is also of interest to monitor poorly instrumented volcanoes from space. © Author(s) 2013.
BibTeX:
@article{BoichuMenutKhvorostyanovEtAl2013,
  author = {Boichu, M. and Menut, L. and Khvorostyanov, D. and Clarisse, L. and Clerbaux, C. and Turquety, S.},
  title = {Inverting for volcanic SO2 flux at high temporal resolution using spaceborne plume imagery and chemistry-transport modelling: the 2010 Eyjafjallajökull eruption case study},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {8569-8584},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879981106&doi=10.5194%2facp-13-8569-2013&partnerID=40&md5=2076c37a5169ae2119126eee96741d48},
  doi = {10.5194/acp-13-8569-2013}
}
Abstract: Atmospheric aerosols impact air quality and global climate. Space based measurements are the best way to observe their spatial and temporal distributions, and can also be used to gain better understanding of their chemical, physical and optical properties. Aerosol composition is the key parameter affecting the refractive index, which determines how much radiation is scattered and absorbed. Composition of aerosols is unfortunately not measured by state of the art satellite remote sounders. Here we use high resolution infrared measurements for aerosol type differentiation, exploiting, in that part of spectrum, the dependency of their refractive index on wavelength. We review existing detection methods and present a unified detection method based on linear discrimination analysis. We demonstrate this method on measurements of the Infrared Atmospheric Sounding Interferometer (IASI) and five different aerosol types, namely volcanic ash, windblown sand, sulfuric acid droplets, ammonium sulfate and smoke particles. We compare these with traditional MODIS AOD measurements. The detection of the last three types is unprecedented in the infrared in nadir mode, but is very promising, especially for sulfuric acid droplets which are detected in the lower troposphere and up to 6 months after injection in the upper troposphere/lower stratosphere. © 2013 Author(s).
BibTeX:
@article{ClarisseCoheurPrataEtAl2013,
  author = {Clarisse, L. and Coheur, P.-F. and Prata, F. and Hadji-Lazaro, J. and Hurtmans, D. and Clerbaux, C.},
  title = {A unified approach to infrared aerosol remote sensing and type specification},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {2195-2221},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874427903&doi=10.5194%2facp-13-2195-2013&partnerID=40&md5=4eaaf6c477a096da9153bd3567c624ce},
  doi = {10.5194/acp-13-2195-2013}
}
BibTeX:
@article{ClerbauxCrevoisier2013,
  author = {Clerbaux, C. and Crevoisier, C.},
  title = {New Directions: Infrared remote sensing of the troposphere from satellite: Less, but better},
  journal = {Atmospheric Environment},
  year = {2013},
  volume = {72},
  pages = {24-26},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875276362&doi=10.1016%2fj.atmosenv.2013.01.057&partnerID=40&md5=596f1999660e73a0052d33611e55ec7b},
  doi = {10.1016/j.atmosenv.2013.01.057}
}
Abstract: Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm-1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO 2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009-2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform infraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values. © Author(s) 2013.
BibTeX:
@article{DuflotHurtmansClarisseEtAl2013,
  author = {Duflot, V. and Hurtmans, D. and Clarisse, L. and R'honi, Y. and Vigouroux, C. and De Mazière, M. and Mahieu, E. and Servais, C. and Clerbaux, C. and Coheur, P.-F.},
  title = {Measurements of hydrogen cyanide (HCN) and acetylene (C2H 2) from the Infrared Atmospheric Sounding Interferometer (IASI)},
  journal = {Atmospheric Measurement Techniques},
  year = {2013},
  volume = {6},
  pages = {917-925},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84882759273&doi=10.5194%2famt-6-917-2013&partnerID=40&md5=48fdb7b8aed7376fa2799d9ce7518bd4},
  doi = {10.5194/amt-6-917-2013}
}
Abstract: To estimate the sea level rise (SLR) originating from changes in surface mass balance (SMB) of the Greenland ice sheet (GrIS), we present 21st century climate projections obtained with the regional climate model MAR (Modèle Atmosphérique Régional), forced by output of three CMIP5 (Coupled Model Intercomparison Project Phase 5) general circulation models (GCMs). Our results indicate that in a warmer climate, mass gain from increased winter snowfall over the GrIS does not compensate mass loss through increased meltwater run-off in summer. Despite the large spread in the projected near-surface warming, all the MAR projections show similar non-linear increase of GrIS surface melt volume because no change is projected in the general atmospheric circulation over Greenland. By coarsely estimating the GrIS SMB changes from GCM output, we show that the uncertainty from the GCM-based forcing represents about half of the projected SMB changes. In 2100, the CMIP5 ensemble mean projects a GrIS SMB decrease equivalent to a mean SLR of +4±2cm and +9±4cm for the RCP (Representative Concentration Pathways) 4.5 and RCP 8.5 scenarios respectively. These estimates do not consider the positive melt-elevation feedback, although sensitivity experiments using perturbed ice sheet topographies consistent with the projected SMB changes demonstrate that this is a significant feedback, and highlight the importance of coupling regional climate models to an ice sheet model. Such a coupling will allow the assessment of future response of both surface processes and ice-dynamic changes to rising temperatures, as well as their mutual feedbacks. © Author(s) 2013. CC Attribution 3.0 License.
BibTeX:
@article{FettweisFrancoTedescoEtAl2013,
  author = {Fettweis, X. and Franco, B. and Tedesco, M. and Van Angelen, J.H. and Lenaerts, J.T.M. and Van Den Broeke, M.R. and Gallée, H.},
  title = {Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR},
  journal = {Cryosphere},
  year = {2013},
  volume = {7},
  pages = {469-489},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937031136&doi=10.5194%2ftc-7-469-2013&partnerID=40&md5=88cb2309cb2a5fe3e9ae38b7dc438892},
  doi = {10.5194/tc-7-469-2013}
}
Abstract: In this study, simulations at 25 km resolution are performed over the Greenland ice sheet (GrIS) throughout the 20th and 21st centuries, using the regional climate model MAR forced by four RCP scenarios from three CMIP5 global circulation models (GCMs), in order to investigate the projected changes of the surface energy balance (SEB) components driving the surface melt. Analysis of 2000-2100 melt anomalies compared to melt results over 1980-1999 reveals an exponential relationship of the GrIS surface melt rate simulated by MAR to the near-surface air temperature (TAS) anomalies, mainly due to the surface albedo positive feedback associated with the extension of bare ice areas in summer. On the GrIS margins, the future melt anomalies are preferentially driven by stronger sensible heat fluxes, induced by enhanced warm air advection over the ice sheet. Over the central dry snow zone, the surface albedo positive feedback induced by the increase in summer melt exceeds the negative feedback of heavier snowfall for TAS anomalies higher than 4 C. In addition to the incoming longwave flux increase associated with the atmosphere warming, GCM-forced MAR simulations project an increase of the cloud cover decreasing the ratio of the incoming shortwave versus longwave radiation and dampening the albedo feedback. However, it should be noted that this trend in the cloud cover is contrary to that simulated by ERA-Interim-forced MAR for recent climate conditions, where the observed melt increase since the 1990s seems mainly to be a consequence of more anticyclonic atmospheric conditions. Finally, no significant change is projected in the length of the melt season, which highlights the importance of solar radiation absorbed by the ice sheet surface in the melt SEB. © Author(s) 2013. CC Attribution 3.0 License.
BibTeX:
@article{FrancoFettweisErpicum2013,
  author = {Franco, B. and Fettweis, X. and Erpicum, M.},
  title = {Future projections of the Greenland ice sheet energy balance driving the surface melt},
  journal = {Cryosphere},
  year = {2013},
  volume = {7},
  pages = {1-18},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873634308&doi=10.5194%2ftc-7-1-2013&partnerID=40&md5=6d71e5aba3ccce35300b5e9b1950364b},
  doi = {10.5194/tc-7-1-2013}
}
Abstract: Validation of ozone profiles measured from a nadir looking satellite instrument over Antarctica is a challenging task due to differences in their vertical sensitivity with ozonesonde measurements. In this paper, ozone observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) instrument onboard the polar-orbiting satellite MetOp are compared with ozone profiles collected between August and October 2010 at McMurdo Station, Antarctica, during the Concordiasi measurement campaign. The main objective of the campaign was the satellite data validation. With this aim 20 zero-pressure sounding balloons carrying ozonesondes were launched during this period when the MetOp satellite was passing above McMurdo. This makes the dataset relevant for comparison, especially because the balloons covered the entire altitude range of IASI profiles. The validation methodology and the collocation criteria vary according to the availability of global positioning system auxiliary data with each electro-chemical cell ozonesonde observation. The relative mean difference is shown to depend on the vertical range investigated. The analysis shows a good agreement in the troposphere (below 10 km) and middle stratosphere (25-40 km), where the differences are lower than 10%. However a significant positive bias of about 10-26% is estimated in the lower stratosphere at 10-25 km, depending on altitude. The positive bias in the 10-25 km range is consistent with previously reported studies comparing in situ data with thermal infrared satellite measurements. This study allows for a better characterization of IASI-retrieved ozone over the polar region during ozone depletion/recovery processes. © Author(s) 2013.
BibTeX:
@article{GazeauxClerbauxGeorgeEtAl2013,
  author = {Gazeaux, J. and Clerbaux, C. and George, M. and Hadji-Lazaro, J. and Kuttippurath, J. and Coheur, P.-F. and Hurtmans, D. and Deshler, T. and Kovilakam, M. and Campbell, P. and Guidard, V. and Rabier, F. and Thépaut, J.-N.},
  title = {Intercomparison of polar ozone profiles by IASI/MetOp sounder with 2010 Concordiasi ozonesonde observations},
  journal = {Atmospheric Measurement Techniques},
  year = {2013},
  volume = {6},
  pages = {613-620},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84882767865&doi=10.5194%2famt-6-613-2013&partnerID=40&md5=035d1435eb58ae0a86bcf3db1a12b42e},
  doi = {10.5194/amt-6-613-2013}
}
Abstract: We present the results of total column measurements of CO, C2H6 and fine-mode aerosol optical depth (AOD) during the "Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites" (BORTAS-B) campaign over eastern Canada. Ground-based observations, using Fourier transform spectrometers (FTSs) and sun photometers, were carried out in July and August 2011. These measurements were taken in Halifax, Nova Scotia, which is an ideal location to monitor the outflow of boreal fires from North America, and also in Toronto, Ontario. Measurements of fine-mode AOD enhancements were highly correlated with enhancements in coincident trace gas (CO and C2H6) observations between 19 and 21 July 2011, which is typical for a smoke plume event. In this paper, we focus on the identification of the origin and the transport of this smoke plume. We use back trajectories calculated by the Canadian Meteorological Centre as well as FLEXPART forward trajectories to demonstrate that the enhanced CO, C2H6 and fine-mode AOD seen near Halifax and Toronto originated from forest fires in northwestern Ontario that occurred between 17 and 19 July 2011. In addition, total column measurements of CO from the satellite-borne Infrared Atmospheric Sounding Interferometer (IASI) have been used to trace the smoke plume and to confirm the origin of the CO enhancement. Furthermore, the enhancement ratio-that is, in this case equivalent to the emission ratio (ERC2H6/CO)-was estimated from these ground-based observations. These C2H6 emission results from boreal fires in northwestern Ontario agree well with C2H6 emission measurements from other boreal regions, and are relatively high compared to fires from other geographical regions. The ground-based CO and C2H6 observations were compared with outputs from the 3-D global chemical transport model GEOS-Chem, using the Fire Locating And Modeling of Burning Emissions (FLAMBE) inventory. Agreement within the stated measurement uncertainty (∼3% for CO and ∼8% for C2H6) was found for the magnitude of the enhancement of the CO and C2H6 total columns between the measured and modelled results. However, there is a small shift in time (of approximately 6 h) of arrival of the plume over Halifax between the results. © Author(s) 2013.
BibTeX:
@article{GriffinWalkerFranklinEtAl2013,
  author = {Griffin, D. and Walker, K.A. and Franklin, J.E. and Parrington, M. and Whaley, C. and Hopper, J. and Drummond, J.R. and Palmer, P.I. and Strong, K. and Duck, T.J. and Abboud, I. and Bernath, P.F. and Clerbaux, C. and Coheur, P.-F. and Curry, K.R. and Dan, L. and Hyer, E. and Kliever, J. and Lesins, G. and Maurice, M. and Saha, A. and Tereszchuk, K. and Weaver, D.},
  title = {Investigation of CO, C2H6 and aerosols in a boreal fire plume over eastern Canada during BORTAS 2011 using ground-and satellite-based observations and model simulations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {10227-10241},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881231175&doi=10.5194%2facp-13-10227-2013&partnerID=40&md5=6d0b0aea7689e0bbaa6460fc1fe1cd31},
  doi = {10.5194/acp-13-10227-2013}
}
Abstract: An eight-year long reanalysis of atmospheric composition data covering the period 2003-2010 was constructed as part of the FP7-funded Monitoring Atmospheric Composition and Climate project by assimilating satellite data into a global model and data assimilation system. This reanalysis provides fields of chemically reactive gases, namely carbon monoxide, ozone, nitrogen oxides, and formaldehyde, as well as aerosols and greenhouse gases globally at a horizontal resolution of about 80 km for both the troposphere and the stratosphere. This paper describes the assimilation system for the reactive gases and presents validation results for the reactive gas analysis fields to document the data set and to give a first indication of its quality. Tropospheric CO values from the MACC reanalysis are on average 10-20% lower than routine observations from commercial aircrafts over airports through most of the troposphere, and have larger negative biases in the boundary layer at urban sites affected by air pollution, possibly due to an underestimation of CO or precursor emissions. Stratospheric ozone fields from the MACC reanalysis agree with ozonesondes and ACE-FTS data to within ±10% in most seasons and regions. In the troposphere the reanalysis shows biases of -5% to +10% with respect to ozonesondes and aircraft data in the extratropics, but has larger negative biases in the tropics. Area-averaged total column ozone agrees with ozone fields from a multi-sensor reanalysis data set to within a few percent. NO2 fields from the reanalysis show the right seasonality over polluted urban areas of the NH and over tropical biomass burning areas, but underestimate wintertime NO2 maxima over anthropogenic pollution regions and overestimate NO2 in northern and southern Africa during the tropical biomass burning seasons. Tropospheric HCHO is well simulated in the MACC reanalysis even though no satellite data are assimilated. It shows good agreement with independent SCIAMACHY retrievals over regions dominated by biogenic emissions with some anthropogenic input, such as the eastern US and China, and also over African regions influenced by biogenic sources and biomass burning. © Author(s) 2013.
BibTeX:
@article{InnessBaierBenedettiEtAl2013,
  author = {Inness, A. and Baier, F. and Benedetti, A. and Bouarar, I. and Chabrillat, S. and Clark, H. and Clerbaux, C. and Coheur, P. and Engelen, R.J. and Errera, Q. and Flemming, J. and George, M. and Granier, C. and Hadji-Lazaro, J. and Huijnen, V. and Hurtmans, D. and Jones, L. and Kaiser, J.W. and Kapsomenakis, J. and Lefever, K. and Leitão, J. and Razinger, M. and Richter, A. and Schultz, M.G. and Simmons, A.J. and Suttie, M. and Stein, O. and Thépaut, J.-N. and Thouret, V. and Vrekoussis, M. and Zerefos, C.},
  title = {The MACC reanalysis: An 8 yr data set of atmospheric composition},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {4073-4109},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884371621&doi=10.5194%2facp-13-4073-2013&partnerID=40&md5=c07a4fbe28549b58972838ea2af112bd},
  doi = {10.5194/acp-13-4073-2013}
}
Abstract: Aerosols from the Sarychev volcano eruption (Kuril Islands, northeast of Japan) were observed in the Arctic lower stratosphere a few days after the strongest SO2 injection which occurred on 15 and 16 June 2009. From the observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) an estimated 0.9 Tg of sulphur dioxide was injected into the upper troposphere and lower stratosphere (UTLS). The resultant stratospheric sulphate aerosols were detected from satellites by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and from the surface by the Network for the Detection of Atmospheric Composition Changes (NDACC) lidar deployed at OHP (Observatoire de Haute-Provence, France). By the first week of July the aerosol plume had spread out over the entire Arctic region. The Sarychev-induced stratospheric aerosol over the Kiruna region (north of Sweden) was measured by the Stratospheric and Tropospheric Aerosol Counter (STAC) during eight balloon flights planned in August and September 2009. During this balloon campaign the Micro Radiomètre Ballon (MicroRADIBAL) and the Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NOx (SALOMON) remote-sensing instruments also observed these aerosols. Aerosol concentrations returned to near-background levels by spring 2010. The effective radius, the surface area density (SAD), the aerosol extinction, and the total sulphur mass from STAC in situ measurements are enhanced with mean values in the range 0.15-0.21 μm, 5.5-14.7 μm2 cm-3, 5.5-29.5 × 10-4 km-1, and 4.9-12.6 × 10-10 kg[S] kg-1[air], respectively, between 14 km and 18 km. The observed and modelled e-folding time of sulphate aerosols from the Sarychev eruption is around 70-80 days, a value much shorter than the 12-14 months calculated for aerosols from the 1991 eruption of Mt Pinatubo. The OSIRIS stratospheric aerosol optical depth (AOD) at 750 nm is enhanced by a factor of 6, with a value of 0.02 in late July compared to 0.0035 before the eruption. The HadGEM2 and MIMOSA model outputs indicate that aerosol layers in polar region up to 14-15 km are largely modulated by stratosphere-troposphere exchange processes. The spatial extent of the Sarychev plume is well represented in the HadGEM2 model with lower altitudes of the plume being controlled by upper tropospheric troughs which displace the plume downward and upper altitudes around 18-20 km, in agreement with lidar observations. Good consistency is found between the HadGEM2 sulphur mass density and the value inferred from the STAC observations, with a maximum located about 1 km above the tropopause ranging from 1 to 2 × 10 -9 kg[S] kg-1[air], which is one order of magnitude higher than the background level. © Author(s) 2013.
BibTeX:
@article{JegouBerthetBrogniezEtAl2013,
  author = {Jégou, F. and Berthet, G. and Brogniez, C. and Renard, J.-B. and François, P. and Haywood, J.M. and Jones, A. and Bourgeois, Q. and Lurton, T. and Auriol, F. and Godin-Beekmann, S. and Guimbaud, C. and Krysztofiak, G. and Gaubicher, B. and Chartier, M. and Clarisse, L. and Clerbaux, C. and Balois, J.Y. and Verwaerde, C. and Daugeron, D.},
  title = {Stratospheric aerosols from the Sarychev volcano eruption in the 2009 Arctic summer},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {6533-6552},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880624661&doi=10.5194%2facp-13-6533-2013&partnerID=40&md5=24a242a6a5ed01e2066e9d8c6e07678b},
  doi = {10.5194/acp-13-6533-2013}
}
Abstract: The fires around Moscow in July and August 2010 emitted a large amount of pollutants to the atmosphere. Here we estimate the carbon monoxide (CO) source strength of the Moscow fires in July and August by using the TM5-4DVAR system in combination with CO column observations of the Infrared Atmospheric Sounding Interferometer (IASI). It is shown that the IASI observations provide a strong constraint on the total emissions needed in the model. Irrespective of the prior emissions used, the optimised CO fire emission estimates from mid-July to mid-August 2010 amount to approximately 24TgCO. This estimate depends only weakly (< 15%) on the assumed diurnal variations and injection height of the emissions. However, the estimated emissions might depend on unaccounted model uncertainties such as vertical transport. Our emission estimate of 22-27 TgCO during roughly one month of intense burning is less than suggested by another recent study, but substantially larger than predicted by the bottom-up inventories. This latter discrepancy suggests that bottom-up emission estimates for extreme peat burning events require improvements. © Author(s) 2013.
BibTeX:
@article{KrolPetersHooghiemstraEtAl2013,
  author = {Krol, M. and Peters, W. and Hooghiemstra, P. and George, M. and Clerbaux, C. and Hurtmans, D. and McInerney, D. and Sedano, F. and Bergamaschi, P. and El Hajj, M. and Kaiser, J.W. and Fisher, D. and Yershov, V. and Muller, J.-P.},
  title = {How much CO was emitted by the 2010 fires around Moscow?},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {4737-4747},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896693875&doi=10.5194%2facp-13-4737-2013&partnerID=40&md5=3e11832d8084abc081e88a3ea385320a},
  doi = {10.5194/acp-13-4737-2013}
}
Abstract: During the last decades, remote sensing sounders have demonstrated their capability for monitoring atmospheric composition and pollution. With now 5 years of continuous observations of IASI instrument, flying on board of MetOp-A platform, we are able to analyze long term variations of atmospheric molecules. This article involves new tendencies for CO and CO2 molecules based on IASI LIC radiances. Comparisons with total columns are also provided. © 2013 AIP Publishing LLC.
BibTeX:
@conference{OudotClerbauxLazaroEtAl2013,
  author = {Oudot, C. and Clerbaux, C. and Lazaro, J.H. and George, M. and Safieddine, S. and Clarisse, L. and Hurtmans, D. and Coheur, P.},
  title = {IASI/MetOp sounder contribution for atmospheric composition monitoring: 4-year study of radiance data},
  journal = {AIP Conference Proceedings},
  year = {2013},
  volume = {1531},
  pages = {212-215},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877869764&doi=10.1063%2f1.4804744&partnerID=40&md5=ebcb930fd56892fa153dceab76107b7e},
  doi = {10.1063/1.4804744}
}
Abstract: In July 2010, several hundred forest and peat fires broke out across central Russia during its hottest summer on record. Here, we analyze these wildfires using observations of the Infrared Atmospheric Sounding Interferometer (IASI). Carbon monoxide (CO), ammonia (NH3) and formic acid (HCOOH) total columns are presented for the year 2010. Maximum total columns were found to be one order (for CO and HCOOH) and two orders (for NH3) of magnitude larger than typical background values. The temporal evolution of NH3 and HCOOH enhancement ratios relative to CO are presented. Evidence of secondary formation of HCOOH is found, with enhancement ratios exceeding reported emission ratios in fresh plumes. We estimate the total emitted masses for the period July-August 2010 over the center of western Russia; they are 19-33 Tg (CO), 0.7-2.6 Tg (NH3) and 0.9-3.9 Tg (HCOOH). For NH3 and HCOOH, these quantities are comparable to what is emitted in the course of a whole year by all extratropical forest fires. © Author(s) 2013.
BibTeX:
@article{RHoniClarisseClerbauxEtAl2013,
  author = {R'Honi, Y. and Clarisse, L. and Clerbaux, C. and Hurtmans, D. and Duflot, V. and Turquety, S. and Ngadi, Y. and Coheur, P.-F.},
  title = {Exceptional emissions of NH3 and HCOOH in the 2010 Russian wildfires},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {4171-4181},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883509311&doi=10.5194%2facp-13-4171-2013&partnerID=40&md5=f325574e79e44d4cea85f07ec59fd67d},
  doi = {10.5194/acp-13-4171-2013}
}
Abstract: Sulfur concentrations have been measured in 28 melt inclusions (MIs) in plagioclase, clinopyroxene, and olivine crystals extracted from tephra produced during the explosive eruption of Grímsvötn in May 2011. The results are compared to sulfur concentrations in the groundmass glass in order to estimate the mass of sulfur brought to surface during the eruption. Satellite measurements yield order of magnitude lower sulfur (~0.2 Tg) in the eruption plume than estimated from the difference between MI and the groundmass glass. This sulfur "deficit" is readily explained by sulfur adhering to tephra grains but principally by sulfide globules caused by basalt-sulfide melt exsolution before degassing. A mass balance calculation reveals that approximately ~0.8 Tg of SO2 is present as globules, representing ~50% of the total sulfur budget. Most of the sulfide globules likely reside at depth due to their elevated density, for potential later remobilization by new magma or hydrothermal circulation. Key Points H2S and SO2 degassing is estimated for the 2011 eruption of Grímsvötn Satellite-based SO2 mass loading is lower than from mineral melt inclusions Half of S resides as sulfide globules; 25% enter the stratosphere ©2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{SigmarssonHaddadiCarnEtAl2013,
  author = {Sigmarsson, O. and Haddadi, B. and Carn, S. and Moune, S. and Gudnason, J. and Yang, K. and Clarisse, L.},
  title = {The sulfur budget of the 2011 Grímsvötn eruption, Iceland},
  journal = {Geophysical Research Letters},
  year = {2013},
  volume = {40},
  pages = {6095-6100},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889956539&doi=10.1002%2f2013GL057760&partnerID=40&md5=8d87da801c240b22ad0e74371dac4fd3},
  doi = {10.1002/2013GL057760}
}
Abstract: Continuous carbon monoxide (CO) total column densities above the Universidad Nacional Autónoma de México (UNAM) campus in Mexico City have been derived from solar absorption infrared spectroscopic measurements since October 2007. Its diurnal evolution is used in the present study in conjunction with other ground-based and satellite data to develop a top-down emission estimate of the annual CO emission of the Mexico City Metropolitan Area (MCMA). The growth-rate of the total column around noon under low ventilation conditions is calculated and allows us to derive the average surface emission-flux at UNAM, while similar measurements taken at the edge of the MCMA in Tecámac provide information on background CO levels in the Mexico basin. Based on 3 yr of measurements, CO column measurements from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument are used to reconstruct the spatial distribution of this anthropogenic pollutant over the MCMA. The agreement between the measured columns of the satellite and ground-based measurements is excellent, particularly when a comparison strategy based on time-displaced air masses is used. The annual emission of the Mexico Megacity is estimated to be (2.15 ± 0.5) Tg yr-1 for the year 2008, while the official inventory for that year reported 1.6 Tg yr -1. The difference is slightly higher than the conservative uncertainty estimated in this work suggesting that the emission might be underestimated by the conventional bottom-up method. A larger discrepancy is found in the spatial distribution of the emissions, when comparing the emission flux over UNAM (derived from the ground-based measurement) with that of the inventory integrated over a representative area. The methodology presented here represents a new and useful strategy to evaluate the contribution of megacities to the global anthropogenic gas emissions. Additionally, three different strategies to compare ground and space-based measurements above an inhomogeneous and strongly contaminated area like Mexico City are presented and discussed. © Author(s) 2013.
BibTeX:
@article{StremmeGrutterRiveraEtAl2013,
  author = {Stremme, W. and Grutter, M. and Rivera, C. and Bezanilla, A. and Garcia, A.R. and Ortega, I. and George, M. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Hannigan, J.W. and Coffey, M.T.},
  title = {Top-down estimation of carbon monoxide emissions from the Mexico Megacity based on FTIR measurements from ground and space},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {1357-1376},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873527973&doi=10.5194%2facp-13-1357-2013&partnerID=40&md5=aef3d0017a69b12c28f65a5fe6fc37b5},
  doi = {10.5194/acp-13-1357-2013}
}
Abstract: Existing descriptions of bi-directional ammonia (NH3) land-atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully simulated the main spatial patterns on local to global scales, it fails to address the environment- and climate- dependence of emissions. To handle these issues, we outline the basis for a new modelling paradigm where both NH3 emissions and deposition are calculated online according to diurnal, seasonal and spatial differences in meteorology. We show how measurements reveal a strong, but complex pattern of climatic dependence, which is increasingly being characterized using ground-based NH3 monitoring and satellite observations, while advances in process-based modelling are illustrated for agricultural and natural sources, including a global application for seabird colonies. A future architecture for NH3 emission-deposition modelling is proposed that integrates the spatio-temporal interactions, and provides the necessary © 2013 The Author(s) Published by the Royal Society. All rights reserved.
BibTeX:
@article{SuttonReisRiddickEtAl2013,
  author = {Sutton, M.A. and Reis, S. and Riddick, S.N. and Dragosits, U. and Nemitz, E. and Theobald, M.R. and Tang, Y.S. and Braban, C.F. and Vieno, M. and Dore, A.J. and Mitchell, R.F. and Wanless, S. and Daunt, F. and Fowler, D. and Blackall, T.D. and Milford, C. and Flechard, C.R. and Loubet, B. and Massad, R. and Cellier, P. and Personne, E. and Coheur, P.F. and Clarisse, L. and Van Damme, M. and Ngadi, Y. and Clerbaux, C. and Skjøth, C.A. and Geels, C. and Hertel, O. and Kruit, R.J.W. and Pinder, R.W. and Bash, J.O. and Walker, J.T. and Simpson, D. and Horváth, L. and Misselbrook, T.H. and Bleeker, A. and Dentener, F. and de Vries, W.},
  title = {Towards a climate-dependent paradigm of ammonia emission and deposition},
  journal = {Philosophical Transactions of the Royal Society B: Biological Sciences},
  year = {2013},
  volume = {368},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878222492&doi=10.1098%2frstb.2013.0166&partnerID=40&md5=d45a52729a21d4a026daee06594f2512},
  doi = {10.1098/rstb.2013.0166}
}
Abstract: To further our understanding of the effects of biomass burning emissions on atmospheric composition, the BORTAS campaign (BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) was conducted on 12 July to 3 August 2011 during the boreal forest fire season in Canada. The simultaneous aerial, ground and satellite measurement campaign sought to record instances of boreal biomass burning to measure the tropo-spheric volume mixing ratios (VMRs) of short- and long-lived trace molecular species from biomass burning emissions. The goal was to investigate the connection between the composition and the distribution of these pyrogenic outflows and their resulting perturbation to atmospheric chemistry, with particular focus on oxidant species to determine the overall impact on the oxidizing capacity of the free troposphere. Measurements of pyrogenic trace species in boreal biomass burning plumes were made by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) onboard the Canadian Space Agency (CSA) SCISAT-1 satellite during the BORTAS campaign. Even though biomass burning emissions are typically confined to the boundary layer, outflows are often injected into the upper troposphere by isolated convection and fire-related convective processes, thus allowing space-borne instruments to measure these pyrogenic outflows. An extensive set of 14 molecules - CH 3OH, C2H2, C2H6, C 3H6O, CO, HCN, HCOOH, HNO3, H2CO, NO, NO2, OCS, O3, and PAN -have been analysed. Included in this analysis is the calculation of age-dependent sets of enhancement ratios for each of the species originating from fires in North America (Canada, Alaska) and Siberia for a period of up to 7 days. Ratio values for the shorter lived primary pyrogenic species decrease over time primarily due to oxidation by the OH radical as the plume ages and values for longer lived species such as HCN and C2H6 remain relatively unchanged. Increasing negative values are observed for the oxidant species, including O3, indicating a destruction process in the plume as it ages such that concentrations of the oxidant species have dropped below their off-plume values. Results from previous campaigns have indicated that values for the molar ratios of ΔO 3 / ΔCO obtained from the measurements of the pyrogenic outflow from boreal fires are highly variable and range from negative to positive, irrespective of plume age. This variability has been attributed to pollution effects where the pyrogenic outflows have mixed with either local urban NO x emissions or pyrogenic emissions from the long-range transport of older plumes, thus affecting the production of O3 within the plumes. The results from this study have identified another potential cause of the variability in O3 concentrations observed in the measurements of biomass burning emissions, where evidence of stratosphere-troposphere exchange due to the pyroconvective updrafts from fires has been identified. Perturbations caused by the lofted emissions in these fire-aided convective processes may result in the intrusion of stratospheric air masses into the free troposphere and subsequent mixing of stratospheric O3 into the pyrogenic outflows causing fluctuations in observed ΔO3/ΔCO molar ratios. © Author(s) 2013.
BibTeX:
@article{TereszchukGonzalezAbadClerbauxEtAl2013,
  author = {Tereszchuk, K.A. and González Abad, G. and Clerbaux, C. and Hadji-Lazaro, J. and Hurtmans, D. and Coheur, P.-F. and Bernath, P.F.},
  title = {ACE-FTS observations of pyrogenic trace species in boreal biomass burning plumes during BORTAS},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {4529-4541},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881260429&doi=10.5194%2facp-13-4529-2013&partnerID=40&md5=920f91fec066daa0c9fac85a51530557},
  doi = {10.5194/acp-13-4529-2013}
}
Abstract: Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of plumes of SO 2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the ultraviolet-visible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO 2 fluxes, it also enables us to assess the consistency of the SO 2 products from the different sensors used. © 2013 Author(s).
BibTeX:
@article{TheysCampionClarisseEtAl2013,
  author = {Theys, N. and Campion, R. and Clarisse, L. and Brenot, H. and Van Gent, J. and Dils, B. and Corradini, S. and Merucci, L. and Coheur, P.-F. and Van Roozendael, M. and Hurtmans, D. and Clerbaux, C. and Tait, S. and Ferrucci, F.},
  title = {Volcanic SO2 fluxes derived from satellite data: A survey using OMI, GOME-2, IASI and MODIS},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {5945-5968},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879938002&doi=10.5194%2facp-13-5945-2013&partnerID=40&md5=ff5c4571666da35ee4dc4a6509d1a650},
  doi = {10.5194/acp-13-5945-2013}
}
Abstract: We present a regional emission inventory constructed based on satellite observations of fire activity (MODIS) and the ORCHIDEE vegetation model, and its application to air quality forecasting. After a brief description of the variability of fire activity in the Euro-Mediterranean region during the past 8 years, a full evaluation of the emissions is performed for the case study of the summer of 2007, during the large Greek fires event. Therefore, regional simulations undertaken with the CHIMERE chemistry-transport model (CTM) are compared to surface and satellite observations of trace gases and aerosols. © Springer Science+Business Media Dordrecht 2014.
BibTeX:
@article{TurquetyMessinaStromatasEtAl2013,
  author = {Turquety, S. and Messina, P. and Stromatas, S. and Anav, A. and Menut, L. and Bessagnet, B. and Péré, J.-C. and Drobinski, P. and Coheur, P.F. and Rhoni, Y. and Clerbaux, C. and Tanré, D.},
  title = {Impact of Fire Emissions on Air Quality in the Euro-Mediterranean Region},
  journal = {NATO Science for Peace and Security Series C: Environmental Security},
  year = {2013},
  volume = {137},
  pages = {363-367},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885394133&doi=10.1007%2f978-94-007-5577-2_61&partnerID=40&md5=bd2b347fe5ac5e771d46bef55c87f2c1},
  doi = {10.1007/978-94-007-5577-2_61}
}
Abstract: Atmospheric carbon monoxide (CO) distributions are controlled by anthropogenic emissions, biomass burning, transport and oxidation by reaction with the hydroxyl radical (OH). Quantifying trends in CO is therefore important for understanding changes related to all of these contributions. Here we present a comprehensive record of satellite observations from 2000 through 2011 of total column CO using the available measurements from nadir-viewing thermal infrared instruments: MOPITT, AIRS, TES and IASI. We examine trends for CO in the Northern and Southern Hemispheres along with regional trends for Eastern China, Eastern USA, Europe and India. We find that all the satellite observations are consistent with a modest decreasing trend ∼-1 % yr-1 in total column CO over the Northern Hemisphere for this time period and a less significant, but still decreasing trend in the Southern Hemisphere. Although decreasing trends in the United States and Europe have been observed from surface CO measurements, we also find a decrease in CO over E. China that, to our knowledge, has not been reported previously. Some of the interannual variability in the observations can be explained by global fire emissions, but the overall decrease needs further study to understand the implications for changes in anthropogenic emissions. © 2013 Author(s).
BibTeX:
@article{WordenDeeterFrankenbergEtAl2013,
  author = {Worden, H.M. and Deeter, M.N. and Frankenberg, C. and George, M. and Nichitiu, F. and Worden, J. and Aben, I. and Bowman, K.W. and Clerbaux, C. and Coheur, P.F. and De Laat, A.T.J. and Detweiler, R. and Drummond, J.R. and Edwards, D.P. and Gille, J.C. and Hurtmans, D. and Luo, M. and Martínez-Alonso, S. and Massie, S. and Pfister, G. and Warner, J.X.},
  title = {Decadal record of satellite carbon monoxide observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2013},
  volume = {13},
  pages = {837-850},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873053422&doi=10.5194%2facp-13-837-2013&partnerID=40&md5=bac705c0a52ed412a885d4117b2d701b},
  doi = {10.5194/acp-13-837-2013}
}
Abstract: Suspended particles play an important role in coastal waters by controlling to a large extent the variability of the water inherent optical properties (IOPs). In this study, focused on the complex waters of the Southern North Sea, the relationships between the concentration, composition and size of suspended particles and their optical properties (light absorption, and attenuation in the visible and near-infrared spectral regions) are investigated. Over a one-year period, field measurements were carried out along regular transects from the Belgian to the English coasts to cover a wide gradient of water masses. Results show that the area can be divided into three geographical zones, each one having specific biogeochemical and optical properties: Scheldt coastal zone (SCZ), Middle of the Southern North Sea (MSNS) and Thames coastal zone (TCZ). Concentrations of organic (inorganic) particles were always higher in the SCZ (TCZ). The MSNS was characterized by a high proportion of organic particles in low concentration. The spectral shape of particle attenuation reveals a wide range from negative to positive slopes. Particle size distributions reveal a power-law shape along the coasts (especially in the TCZ) and a bimodal distribution in the MSNS notably during the spring phytoplankton bloom. This bimodal size distribution and more precisely a size peak around 7 μm results in an unexpected negative spectral slope of the particle attenuation coefficient. Variations in the particulate mass-specific IOPs between the three regions were observed to predominate over seasonal variations. The implications in terms of inversion of IOPs into biogeochemical parameters, such as chlorophyll a and total suspended matter, in coastal waters are discussed. © 2012 Elsevier Ltd.
BibTeX:
@article{AstorecaDoxaranRuddickEtAl2012,
  author = {Astoreca, R. and Doxaran, D. and Ruddick, K. and Rousseau, V. and Lancelot, C.},
  title = {Influence of suspended particle concentration, composition and size on the variability of inherent optical properties of the Southern North Sea},
  journal = {Continental Shelf Research},
  year = {2012},
  volume = {35},
  pages = {117-128},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856779823&doi=10.1016%2fj.csr.2012.01.007&partnerID=40&md5=0d2e041dd9d5ff74a8b5785b3421b95b},
  doi = {10.1016/j.csr.2012.01.007}
}
Abstract: Using an extended cavity diode laser referenced to a femtosecond frequency comb, the P(11) absorption line in the ν 1+ν 3 combination band of the most abundant isotopologue of pure acetylene was studied at temperatures of 296, 240, 200, 175, 165, 160, 155, and 150 K to determine pressure-dependent line shape parameters at these temperatures. The laser emission profile, the instrumental resolution, is a Lorentz function characterized by a half width at half the maximum emission (HWHM) of 8.3×10-6 cm-1 (or 250 kHz) for these measurements. Six collision models were tested in fitting the experimental data: Voigt, speed-dependent Voigt, Rautian-Sobel'man, Galatry, and two Rautian-Galatry hybrid models (with and without speed-dependence). Only the speed-dependent Voigt model was able to fit the data to the experimental noise level at all temperatures and for pressures between 3 and nearly 360 torr. The variations of the speed-dependent Voigt profile line shape parameters with temperature were also characterized, and this model accurately reproduces the observations over their entire range of temperature and pressure. © 2011 Springer-Verlag.
BibTeX:
@article{CichMcRavenLopezEtAl2012,
  author = {Cich, M.J. and McRaven, C.P. and Lopez, G.V. and Sears, T.J. and Hurtmans, D. and Mantz, A.W.},
  title = {Temperature-dependent pressure broadened line shape measurements in the ν 1+ν 3 band of acetylene using a diode laser referenced to a frequency comb},
  journal = {Applied Physics B: Lasers and Optics},
  year = {2012},
  volume = {109},
  pages = {373-384},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876236153&doi=10.1007%2fs00340-011-4829-0&partnerID=40&md5=c7542305b28fd9620d5b77d4334a0f2c},
  doi = {10.1007/s00340-011-4829-0}
}
Abstract: Thermal infrared sounding of sulphur dioxide (SO 2) from space has gained appreciation as a valuable complement to ultraviolet sounding. There are several strong absorption bands of SO 2 in the infrared, and atmospheric sounders, such as AIRS (Atmospheric Infrared Sounder), TES (Tropospheric Emission Spectrometer) and IASI (Infrared Atmospheric Sounding Interferometer) have the ability to globally monitor SO 2 abundances. Most of the observed SO 2 is found in volcanic plumes. In this paper we outline a novel algorithm for the sounding of SO 2 above ∼5 km altitude using high resolution infrared sounders and apply it to measurements of IASI. The main features of the algorithm are a wide applicable total column range (over 4 orders of magnitude, from 0.5 to 5000 dobson units), a low theoretical uncertainty (3-5%) and near real time applicability. We make an error analysis and demonstrate the algorithm on the recent eruptions of Sarychev, Kasatochi, Grimsvötn, Puyehue-Cordón Caulle and Nabro. © 2012 Author(s). CC Attribution 3.0 License.
BibTeX:
@article{ClarisseHurtmansClerbauxEtAl2012,
  author = {Clarisse, L. and Hurtmans, D. and Clerbaux, C. and Hadji-Lazaro, J. and Ngadi, Y. and Coheur, P.-F.},
  title = {Retrieval of sulphur dioxide from the infrared atmospheric sounding interferometer (IASI)},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {581-594},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858717212&doi=10.5194%2famt-5-581-2012&partnerID=40&md5=199d20b2ab418b76910b5acbba8a75a2},
  doi = {10.5194/amt-5-581-2012}
}
Abstract: The IASI (Infrared Atmospheric Sounding Interferometer) nadir-looking thermal infrared sounder onboard MetOp-A enables the monitoring of atmospheric constituents on a global scale. This paper presents a quality assessment of IASI CO profiles retrieved by the two different retrieval algorithms SOFRID and FORLI, by an intercomparison with airborne in-situ CO profiles from the MOZAIC program for the 2008-2009 period. Lower (surface-480 hPa) and upper tropospheric partial column (480-225 hPa) comparisons as well as profile comparisons are made. The retrieval errors of the IASI products are less than 21% in the lower troposphere and less than 10% in the upper troposphere. A statistical analysis shows similar correlation coefficients for the two retrieval algorithms and smoothed MOZAIC of r ∼ 0.8 and r ∼ 0.7 in the lower and upper troposphere respectively. Comparison with smoothed MOZAIC data of the temporal variation of the CO profiles at the airports of Frankfurt and Windhoek demonstrates that the IASI products are able to capture the seasonal variability at these sites. At Frankfurt SOFRID (respectively FORLI) is positively biased by 10.5% (13.0%) compared to smoothed MOZAIC in the upper (lower) troposphere, and the limited sensitivity of the IASI instrument to the boundary layer when thermal contrast is low is identified. At Windhoek, the impact of the vegetation fires in Southern Africa from July to November is captured by both SOFRID and FORLI, with an overestimation of the CO background values (fire maxima) by SOFRID (FORLI) by 12.8% (10%). Profile comparisons at Frankfurt and Windhoek show that the largest discrepancies are found between the two IASI products and MOZAIC for the nighttime retrievals. © 2012 Author(s).
BibTeX:
@article{DeWachterBarretLeFlochmoenEtAl2012,
  author = {De Wachter, E. and Barret, B. and Le Flochmoën, E. and Pavelin, E. and Matricardi, M. and Clerbaux, C. and Hadji-Lazaro, J. and George, M. and Hurtmans, D. and Coheur, P.-F. and Nedelec, P. and Cammas, J.P.},
  title = {Retrieval of MetOp-A/IASI CO profiles and validation with MOZAIC data},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {2843-2857},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880800964&doi=10.5194%2famt-5-2843-2012&partnerID=40&md5=22fb025ad36358a0fbfc1c5ef75e9ecf},
  doi = {10.5194/amt-5-2843-2012}
}
Abstract: Three scientific ozone products from the Infrared Atmospheric Sounding Interferometer (IASI) aboard MetOp-A, retrieved in three different research teams (LA, LATMOS/ULB, LISA) with different retrieval schemes, are characterized and validated using ozonesondes measurements. The characteristics of the products are analyzed in terms of retrieval sensitivity, systematic and random errors, and ability to retrieve the natural variability of ozone and focus on different partial columns from the lower troposphere up to 30 km. The validation covers the midlatitudes and the tropics and the period from January to December 2008. The products present degrees of freedom (DOF) in the troposphere between 1 and 1.2 on average in the midlatitudes and between 1 and 1.4 in the tropics. The DOF are distributed differently on the vertical depending on the profiles and the season: summer leading to a better sensitivity to the lower troposphere, as expected. The error estimates range between 10 and 20% from the lower tropospheric partial columns (0-6 km and 0-8 km for the midlatitudes and the tropics respectively) to the UTLS partial columns (8-16 km and 11-20 km for the midlatitudes and the tropics respectively) for all the products and are about 5% in the stratosphere (16-30 km) and for the column up to 30 km. The main feature that arises from the comparison with the ozonesondes is a systematic overestimation of ozone in the UTLS (between 10 and 25%) by the three products in the midlatitudes and the tropics, attributed to the moderate vertical resolution of IASI and possibly to spectroscopic inconsistencies. The ability of the products to reproduce natural variability of tropospheric ozone is fairly good and depends on the considered season and region. © 2012 Author(s).
BibTeX:
@article{DufourEremenkoGriesfellerEtAl2012,
  author = {Dufour, G. and Eremenko, M. and Griesfeller, A. and Barret, B. and Leflochmoën, E. and Clerbaux, C. and Hadji-Lazaro, J. and Coheur, P.-F. and Hurtmans, D.},
  title = {Validation of three different scientific ozone products retrieved from IASI spectra using ozonesondes},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {611-630},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861371381&doi=10.5194%2famt-5-611-2012&partnerID=40&md5=8abe956a20bde9cdd116b2eb99344e8e},
  doi = {10.5194/amt-5-611-2012}
}
Abstract: With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-INTERIM reanalysis. This comparison revealed that (i) the inter-annual variability of the SMB components is consistent within the different spatial resolutions investigated, (ii) the MAR model simulates heavier precipitation on average over the GrIS with decreasing spatial resolution, and (iii) the SMB components (except precipitation) can be derived from a simulation at lower resolution with an "intelligent" interpolation. This interpolation can also be used to approximate the SMB components over another topography/ice sheet mask of the GrIS. These results are important for the forcing of an ice dynamical model needed to enable future projections of the GrIS contribution to sea level rise over the coming centuries. © 2013 Author(s).
BibTeX:
@article{FrancoFettweisLangEtAl2012,
  author = {Franco, B. and Fettweis, X. and Lang, C. and Erpicum, M.},
  title = {Impact of spatial resolution on the modelling of the Greenland ice sheet surface mass balance between 1990-2010, using the regional climate model MAR},
  journal = {Cryosphere},
  year = {2012},
  volume = {6},
  pages = {695-711},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865160984&doi=10.5194%2ftc-6-695-2012&partnerID=40&md5=c90abd54e3962dfc4ceb933644b800f3},
  doi = {10.5194/tc-6-695-2012}
}
Abstract: The global distribution of dust column burden derived from MODIS Deep Blue aerosol products is compared to NH 3 column burden retrieved from IASI infrared spectra. We found similarities in their spatial distributions, in particular their hot spots are often collocated over croplands and to a lesser extent pastures. Globally, we found 22% of dust burden collocated with NH 3, with only 1% difference between land-use databases. This confirms the importance of anthropogenic dust from agriculture. Regionally, the Indian subcontinent has the highest amount of dust mixed with NH 3 (26%), mostly over cropland and during the pre-monsoon season. North Africa represents 50% of total dust burden but accounts for only 4% of mixed dust, which is found over croplands and pastures in Sahel and the coastal region of the Mediterranean. In order to evaluate the radiative effect of this mixing on dust optical properties, we derive the mass extinction efficiency for various mixtures of dust and NH 3, using AERONET sunphotometers data. We found that for dusty days the coarse mode mass extinction efficiency decreases from 0.62 to 0.48 m 2 g -1 as NH 3 burden increases from 0 to 40 mg m -2. The fine mode extinction efficiency, ranging from 4 to 16 m 2 g -1, does not appear to depend on NH 3 concentration or relative humidity but rather on mineralogical composition and mixing with other aerosols. Our results imply that a significant amount of dust is already mixed with ammonium salt before its long range transport. This in turn will affect dust lifetime, and its interactions with radiation and cloud properties. © 2012 Author(s).
BibTeX:
@article{GinouxClarisseClerbauxEtAl2012,
  author = {Ginoux, P. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Dubovik, O. and Hsu, N.C. and Van Damme, M.},
  title = {Mixing of dust and NH 3 observed globally over anthropogenic dust sources},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {7351-7363},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869006576&doi=10.5194%2facp-12-7351-2012&partnerID=40&md5=b106e679418c5d2ccdd15545b1fde629},
  doi = {10.5194/acp-12-7351-2012}
}
Abstract: We use in situ observations from the Interagency Monitoring of PROtected Visual Environments (IMPROVE) network, the Midwest Ammonia Monitoring Project, 11 surface site campaigns as well as Infrared Atmospheric Sounding Interferometer (IASI) satellite measurements with the GEOS-Chem model to investigate inorganic aerosol loading and atmospheric ammonia concentrations over the United States. IASI observations suggest that current ammonia emissions are underestimated in California and in the springtime in the Midwest. In California this underestimate likely drives the underestimate in nitrate formation in the GEOS-Chem model. However in the remaining continental United States we find that the nitrate simulation is biased high (normalized mean bias &gt; Combining double low line 1.0) year-round, except in Spring (due to the underestimate in ammonia in this season). None of the uncertainties in precursor emissions, the uptake efficiency of N 2O 5 on aerosols, OH concentrations, the reaction rate for the formation of nitric acid, or the dry deposition velocity of nitric acid are able to explain this bias. We find that reducing nitric acid concentrations to 75% of their simulated values corrects the bias in nitrate (as well as ammonium) in the US. However the mechanism for this potential reduction is unclear and may be a combination of errors in chemistry, deposition and sub-grid near-surface gradients. This "updated" simulation reproduces PM and ammonia loading and captures the strong seasonal and spatial gradients in gas-particle partitioning across the United States. We estimate that nitrogen makes up 15-35% of inorganic fine PM mass over the US, and that this fraction is likely to increase in the coming decade, both with decreases in sulfur emissions and increases in ammonia emissions. © 2012 Author(s).
BibTeX:
@article{HealdCollettJr.LeeEtAl2012,
  author = {Heald, C.L. and Collett Jr., J.L. and Lee, T. and Benedict, K.B. and Schwandner, F.M. and Li, Y. and Clarisse, L. and Hurtmans, D.R. and Van Damme, M. and Clerbaux, C. and Coheur, P.-F. and Philip, S. and Martin, R.V. and Pye, H.O.T.},
  title = {Atmospheric ammonia and particulate inorganic nitrogen over the United States},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {10295-10312},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867914496&doi=10.5194%2facp-12-10295-2012&partnerID=40&md5=38877e3555921c49bae5d54e0e91f9ac},
  doi = {10.5194/acp-12-10295-2012}
}
Abstract: The UK Met Office's Numerical Atmospheric-dispersion Modeling Environment (NAME) is used both operationally and for research investigations. It has previously been used to model volcanic ash at the London Volcanic Ash Advisory Centre (VAAC), including that from the eruptions in Iceland of Eyjafjallajökull in 2010 and Grímsvtn in 2011. In this paper, the ability of NAME to model the release and dispersion of volcanic SO2, the chemical processes leading to the production of sulphate aerosol, and the subsequent dispersion of sulphate aerosol, has been investigated. Sensitivity tests were carried out to investigate the suitability of the NAME chemistry scheme for use in both the troposphere and the stratosphere. The eruptions of Sarychev in 2009, Kasatochi in 2008 and Eyjafjallajökull in 2010 were simulated and results for SO2 column density and sulphate aerosol optical depth (AOD) were compared with satellite retrievals. NAME results compare favorably with available observations in terms of both geographical distribution and magnitude for all three cases. The NAME modeled values of SO2 show a correlation of 0.8 with the corresponding observations for Sarychev. Ninety percent of modeled values of northern hemisphere averaged sulphate AOD are within a factor of 2 of those observed for Kasatochi and 71% are within a factor of 2 of those observed for Sarychev. Although significant uncertainties are present in both the model and observations, this work demonstrates that NAME's current chemistry scheme shows promise as a tool for modeling SO2 and sulphate from volcanoes. © 2012 by the American Geophysical Union.
BibTeX:
@article{HeardManningHaywoodEtAl2012,
  author = {Heard, I.P.C. and Manning, A.J. and Haywood, J.M. and Witham, C. and Redington, A. and Jones, A. and Clarisse, L. and Bourassa, A.},
  title = {A comparison of atmospheric dispersion model predictions with observations of SO2 and sulphate aerosol from volcanic eruptions},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2012},
  volume = {117},
  article number = {D00U22},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859467819&doi=10.1029%2f2011JD016791&partnerID=40&md5=c882d1b19cb4dd47f681e245c9e2974a},
  doi = {10.1029/2011JD016791}
}
Abstract: The first Infrared Atmospheric Sounding Interferometer (IASI) was launched in October 2006 on the European Organization for the Exploitation of Meteorological Satellites' (EUMETSAT) Meteorological Operation (MetOp)-A satellite. The instrument and its successors will continue to operate until 2020 on the current MetOp platform and two follow-on satellites. The stability of the instrument is monitored routinely by the CNES Technical Expertise Center, using onboard measurements, and by EUMETSAT, where stable, clear fields of view are compared with simulated radiances from numerical weather prediction model output. Routine monitoring of IASI data and calibration and validation activities by CNES and EUMETSAT ensure full characterization of the instrument and verify that the performance meets the requirements. In-depth evaluation is routinely performed by comparing IASI with other instruments, such as AVHRR and the High Resolution Infrared Radiation Sounder (HIRS) on the MetOp platform.
BibTeX:
@article{HiltonArmanteAugustEtAl2012,
  author = {Hilton, F. and Armante, R. and August, T. and Barnet, C. and Bouchard, A. and Camy-Peyret, C. and Capelle, V. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Collard, A. and Crevoisier, C. and Dufour, G. and Edwards, D. and Faijan, F. and Fourrié, N. and Gambacorta, A. and Goldberg, M. and Guidard, V. and Hurtmans, D. and Illingworth, S. and Jacquinet-Husson, N. and Kerzenmacher, T. and Klaes, D. and Lavanant, L. and Masiello, G. and Matricardi, M. and McNally, A. and Newman, S. and Pavelin, E. and Payan, S. and Péquignot, E. and Peyridieu, S. and Phulpin, T. and Remedios, J. and Schlüssel, P. and Serio, C. and Strow, L. and Stubenrauch, C. and Taylor, J. and Tobin, D. and Wolf, W. and Zhou, D.},
  title = {Hyperspectral earth observation from IASI},
  journal = {Bulletin of the American Meteorological Society},
  year = {2012},
  volume = {93},
  pages = {347-370},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855696187&doi=10.1175%2fBAMS-D-11-00027.1&partnerID=40&md5=ab171da2f23f5fb2f0d96eb8d6ceb877},
  doi = {10.1175/BAMS-D-11-00027.1}
}
Abstract: This paper lays down the theoretical bases and the methods used in the Fast Optimal Retrievals on Layers for IASI (FORLI) software, which is developed and maintained at the "Université Libre de Bruxelles" (ULB) with the support of the "Laboratoire Atmosphères, Milieux, Observations Spatiales" (LATMOS) to process radiance spectra from the Infrared Atmospheric Sounding Interferometer (IASI) in the perspective of local to global chemistry applications. The forward radiative transfer model (RTM) and the retrieval approaches are formulated and numerical approximations are described. The aim of FORLI is near-real-time provision of global scale concentrations of trace gases from IASI, either integrated over the altitude range of the atmosphere (total columns) or vertically resolved. To this end, FORLI uses precalculated table of absorbances. At the time of writing three gas-specific versions of this algorithm have been set up: FORLI-CO, FORLI-O 3 and FORLI-HNO 3. The performances of each are reviewed and illustrations of results and early validations are provided, making the link to recent scientific publications. In this paper we stress the challenges raised by near-real-time processing of IASI, shortly describe the processing chain set up at ULB and draw perspectives for future developments and applications. © 2012 Elsevier Ltd.
BibTeX:
@article{HurtmansCoheurWespesEtAl2012,
  author = {Hurtmans, D. and Coheur, P.-F. and Wespes, C. and Clarisse, L. and Scharf, O. and Clerbaux, C. and Hadji-Lazaro, J. and George, M. and Turquety, S.},
  title = {FORLI radiative transfer and retrieval code for IASI},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2012},
  volume = {113},
  pages = {1391-1408},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860916319&doi=10.1016%2fj.jqsrt.2012.02.036&partnerID=40&md5=9556e0a9c421eeb83eac217b7828dbbf},
  doi = {10.1016/j.jqsrt.2012.02.036}
}
Abstract: Carbon monoxide (CO) is retrieved daily and globally from space-borne IASI radiance spectra using the Fast Optimal Retrievals on Layers for IASI (FORLI) software developed at the Université Libre de Bruxelles (ULB). The IASI CO total column product for 2008 from the most recent FORLI retrieval version (20100815) is evaluated using correlative CO profile products retrieved from ground-based solar absorption Fourier transform infrared (FTIR) observations at the following FTIR spectrometer sites from the Network for the Detection of Atmospheric Composition Change (NDACC): Ny-Ã..lesund, Kiruna, Bremen, Jungfraujoch, Izaña and Wollongong. In order to have good statistics for the comparisons, we included all IASI data from the same day, within a 100 km radius around the ground-based stations. The individual ground-based data were adjusted to the lowest altitude of the co-located IASI CO profiles. To account for the different vertical resolutions and sensitivities of the ground-based and satellite measurements, the averaging kernels associated with the various retrieved products have been used to properly smooth coincident data products. It has been found that the IASI CO total column products compare well on average with the co-located ground-based FTIR total columns at the selected NDACC sites and that there is no significant bias for the mean values at all stations. © 2012 Author(s).
BibTeX:
@article{KerzenmacherDilsKumpsEtAl2012,
  author = {Kerzenmacher, T. and Dils, B. and Kumps, N. and Blumenstock, T. and Clerbaux, C. and Coheur, P.-F. and Demoulin, P. and García, O. and George, M. and Griffith, D.W.T. and Hase, F. and Hadji-Lazaro, J. and Hurtmans, D. and Jones, N. and Mahieu, E. and Notholt, J. and Paton-Walsh, C. and Raffalski, U. and Ridder, T. and Schneider, M. and Servais, C. and De Mazière, M.},
  title = {Validation of IASI FORLI carbon monoxide retrievals using FTIR data from NDACC},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {2751-2761},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869407114&doi=10.5194%2famt-5-2751-2012&partnerID=40&md5=023bf0cb09f99d3a4af836991572dcb1},
  doi = {10.5194/amt-5-2751-2012}
}
Abstract: This work evaluates the IASI CO product against independent in-situ aircraft data from the MOZAIC program and the POLARCAT aircraft campaign. The validation is carried out by analysing the impact of assimilation of eight months of IASI CO columns retrieved for the period of May to December 2008 into the global chemistry transport model LMDz-INCA. A modelling system based on a sub-optimal Kalman filter was developed and a specific treatment that takes into account the representativeness of observations at the scale of the model grid is applied to the IASI CO columns and associated errors before their assimilation in the model. Comparisons of the assimilated CO profiles with in situ CO measurements indicate that the assimilation leads to a considerable improvement of the model simulations in the middle troposphere as compared with a control run with no assimilation. Model biases in the simulation of background values are reduced and improvement in the simulation of very high concentrations is observed. The improvement is due to the transport by the model of the information present in the IASI CO retrievals. Our analysis also shows the impact of assimilation of CO on the representation of transport into the Arctic region during the POLARCAT summer campaign. A considerable increase in CO mixing ratios over the Asian source region was observed when assimilation was used leading to much higher values of CO during the cross-pole transport episode. These higher values are in good agreement with data from the POLARCAT flights that sampled this plume. © 2012 Author(s).
BibTeX:
@article{KloneckiPommierClerbauxEtAl2012,
  author = {Klonecki, A. and Pommier, M. and Clerbaux, C. and Ancellet, G. and Cammas, J.-P. and Coheur, P.-F. and Cozic, A. and Diskin, G.S. and Hadji-Lazaro, J. and Hauglustaine, D.A. and Hurtmans, D. and Khattatov, B. and Lamarque, J.-F. and Law, K.S. and Nedelec, P. and Paris, J.-D. and Podolske, J.R. and Prunet, P. and Schlager, H. and Szopa, S. and Turquety, S.},
  title = {Assimilation of IASI satellite CO fields into a global chemistry transport model for validation against aircraft measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {4493-4512},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861492675&doi=10.5194%2facp-12-4493-2012&partnerID=40&md5=24ca6cbaef75c17ecd7c6b83c379156b},
  doi = {10.5194/acp-12-4493-2012}
}
Abstract: The SPIRALE and SWIR balloon-borne instruments were launched in the Arctic polar region (near Kiruna, Sweden, 67.9° N-21.1° E) during summer on 7 and 24 August 2009 and on 14 August 2009, respectively. The SPIRALE instrument performed in situ measurements of several trace gases including CO and O 3 at altitudes between 9 and 34 km, with very high vertical resolution (∼ 5 m). The SWIR-balloon instrument measured total and partial column of several species including CO. The CO stratospheric profile from SPIRALE for 7 August 2009 shows some specific structures with large concentrations in the low levels (potential temperatures between 320 and 380 K, i.e. 10-14 km height). These structures are not present in the CO vertical profile of SPIRALE for 24 August 2009, for which the volume mixing ratios are typical from polar latitudes (∼ 30 ppb). CO total columns retrieved from the IASI-MetOp satellite sounder for the three dates of flights are used to understand this CO variability. SPIRALE and SWIR CO partial columns between 9 and 34 km are compared, allowing us to confirm that the enhancement of CO is localised in the stratosphere. The measurements are also investigated in terms of CO:O3 correlations and using several modelling approaches (trajectory calculations, potential vorticity fields, results of chemistry transport model) in order to characterize the origin of the air masses sampled. The emission sources are qualified in terms of source type (fires, urban pollution) using NH3 and CO measurements from IASI-MetOp and fires detection from MODIS on board the TERRA/AQUA satellite. The results give strong evidence that the unusual abundance of CO on 7 August is due to surface pollution plumes from East Asia and North America transporting to the upper troposphere and then entering the lower stratosphere by isentropic advection. This study strengthens evidence that the composition of low polar stratosphere in summer may be affected by anthropogenic surface emissions through long-range transport. © 2012 Author(s).
BibTeX:
@article{KrysztofiakThieblemontHuretEtAl2012,
  author = {Krysztofiak, G. and Thiéblemont, R. and Huret, N. and Catoire, V. and Té, Y. and Jégou, F. and Coheur, P.F. and Clerbaux, C. and Payan, S. and Drouin, M.A. and Robert, C. and Jeseck, P. and Attié, J.-L. and Camy-Peyret, C.},
  title = {Detection in the summer polar stratosphere of pollution plume from East Asia and North America by balloon-borne in situ CO measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {11889-11906},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871271060&doi=10.5194%2facp-12-11889-2012&partnerID=40&md5=19ee68e83bf6761348f93c7f1717b6b8},
  doi = {10.5194/acp-12-11889-2012}
}
Abstract: In this paper we retrieve atmospheric HDO, H2O concentrations and their ratio δD from IASI radiances spectra. Our method relies on an existing radiative transfer model (Atmosphit) and an optimal estimation inversion scheme, but goes further than our previous work by explicitly considering correlations between the two species. A global HDO and H 2O a priori profile together with a covariance matrix were built from daily LMDz-iso model simulations of HDO and H2O profiles over the whole globe and a whole year. The retrieval parameters are described and characterized in terms of errors. We show that IASI is mostly sensitive to δD in the middle troposphere and allows retrieving δD for an integrated 3-6 km column with an error of 38‰ on an individual measurement basis. We examine the performance of the retrieval to capture the temporal (seasonal and short-term) and spatial variations of δD for one year of measurement at two dedicated sites (Darwin and Izan∼a) and a latitudinal band from g-60° to 60° for a 15 day period in January. We report a generally good agreement between IASI and the model and indicate the capabilities of IASI to reproduce the large scale variations of δD (seasonal cycle and latitudinal gradient) with good accuracy. In particular, we show that there is no systematic significant bias in the retrieved δD values in comparison with the model, and that the retrieved variability is similar to the one in the model even though there are certain local differences. Moreover, the noticeable differences between IASI and the model are briefly examined and suggest modeling issues instead of retrieval effects. Finally, the results further reveal the unprecedented capabilities of IASI to capture short-term variations in δD, highlighting the added value of the sounder for monitoring hydrological processes. © 2012 Author(s).
BibTeX:
@article{LacourRisiClarisseEtAl2012,
  author = {Lacour, J.-L. and Risi, C. and Clarisse, L. and Bony, S. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {Mid-tropospheric δd observations from IASI/MetOp at high spatial and temporal resolution},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {10817-10832},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869148747&doi=10.5194%2facp-12-10817-2012&partnerID=40&md5=a0d1a820339918b570a88904c1199b8b},
  doi = {10.5194/acp-12-10817-2012}
}
Abstract: Volcanic degassing produces abundant H2O and CO2, as well as SO2, HCl, H2S, S2, H2, HF, CO, and SiF4. Volcanic SO2, HCl, and H2S have been detected from satellites in the past; the remaining species are analyzed in situ or using airborne instruments, with all the consequent limitations in safety and sampling, and at elevated costs. We report identification of high CO concentrations consistent with a volcanic origin (the 2010 Eyjafjallajkull and 2011 Grímsvtn eruptions in Iceland) in data from the Measurements of Pollution in the Troposphere instrument (MOPITT) onboard EOS/Terra. The high CO values coincide spatially and temporally with ash plumes emanating from the eruptive centers, with elevated SO2 and aerosol optical thickness, as well as with high CO values in data from the Infrared Atmospheric Sounding Interferometer (IASI), onboard MetOp-A. CO has a positive indirect radiative forcing; climate models currently do not account for volcanic CO emissions. Given global volcanic CO2 emissions between 130 and 440 Tg/year and volcanic CO:CO2 ratios from the literature, we estimate that average global volcanic CO emissions may be on the order of ∼5.5 Tg/year, equivalent to the CO emissions caused by combined fossil fuel and biofuel combustion in Australia. © 2012. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Martinez-AlonsoDeeterWordenEtAl2012,
  author = {Martínez-Alonso, S. and Deeter, M.N. and Worden, H.M. and Clerbaux, C. and Mao, D. and Gille, J.C.},
  title = {First satellite identification of volcanic carbon monoxide},
  journal = {Geophysical Research Letters},
  year = {2012},
  volume = {39},
  article number = {L21809},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869477137&doi=10.1029%2f2012GL053275&partnerID=40&md5=1370b39aa4f3cae161f090403a1c3b57},
  doi = {10.1029/2012GL053275}
}
Abstract: This study analyzes relationships between concentration of suspended particles represented by dry mass, [SPM], or area, [AC], and optical properties including particulate beam attenuation (cp), side scattering (bs), and backscattering (bbp), obtained from an intensive sampling program in coastal and offshore waters around Europe and French Guyana. First-order optical properties are driven by particle concentration with best predictions of [SPM] by bbp and bs, and of [AC] by cp. Second-order variability is investigated with respect to particle size, apparent density (dry weight-to-wet-volume ratio), and composition. Overall, the mass-specific particulate backscattering coefficient, bmp (=bbp: [SPM]), is relatively well constrained, with variability of a factor of 3-4. This coefficient is well correlated with particle composition, with inorganic particles having values about three times greater (brmp= 0.012 m2 g_1) than organic particles (brmp= 0.005 m2 g_1). The mass-specific particulate attenuation coefficient, cm (= cp: [SPM]), on the other hand, varies over one order of magnitude and is strongly driven (77% of the variability explained) by particle apparent density. In this data set particle size does not affect cm and affects b bmp only weakly in clear (case 1) waters, despite size variations over one order of magnitude. A significant fraction (40-60%) of the variability in bmp remains unexplained. Possible causes are the limitation of the measured size distributions to the 2-302-mm range and effects of particle shape and internal structure that affect bbp more than cp and were not accounted for. © 2012, by the Association for the Sciences of Limnology and Oceanography, Inc.
BibTeX:
@article{NekermansLoiselMeriauxEtAl2012,
  author = {Nekermans, G. and Loisel, H. and Meriaux, X. and Astoreca, R. and McKee, D.},
  title = {In situ variability of mass-specific beam attenuation and backscattering of marine particles with respect to particle size, density, and composition},
  journal = {Limnology and Oceanography},
  year = {2012},
  volume = {57},
  pages = {124-144},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859108649&doi=10.4319%2flo.2011.57.1.0124&partnerID=40&md5=5f0121ab9d7a2480f5fab7c846c9554e},
  doi = {10.4319/lo.2011.57.1.0124}
}
Abstract: An extensive set of airborne and satellite observations of volcanic ash from the Eyjafjallajökull Icelandic eruption are analyzed for a case study on 17 May 2010. Data collected from particle scattering probes and backscatter lidar on the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 aircraft allow estimates of ash concentration to be derived. Using radiative transfer simulations we show that airborne and satellite infrared radiances can be accurately modeled based on the in situ measured size distribution and a mineral dust refractive index. Furthermore, airborne irradiance measurements in the 0.3-1.7 m range are well modeled with these properties. Retrievals of ash mass column loading using Infrared Atmospheric Sounding Interferometer (IASI) observations are shown to be in accord with lidar-derived mass estimates, giving for the first time an independent verification of a hyperspectral ash variational retrieval method. The agreement of the observed and modeled solar and terrestrial irradiances suggests a reasonable degree of radiative closure implying that the physical and optical properties of volcanic ash can be relatively well constrained using data from state-of-the-science airborne platforms such as the FAAM BAe 146 aircraft. Comparisons with IASI measurements during recent Grímsvötn and Puyehue volcanic eruptions demonstrate the importance of accurately specifying the refractive index when modeling the observed spectra.
BibTeX:
@article{NewmanClarisseHurtmansEtAl2012,
  author = {Newman, S.M. and Clarisse, L. and Hurtmans, D. and Marenco, F. and Johnson, B. and Turnbull, K. and Havemann, S. and Baran, A.J. and O'Sullivan, D. and Haywood, J.},
  title = {A case study of observations of volcanic ash from the Eyjafjallajökull eruption: 2. Airborne and satellite radiative measurements},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2012},
  volume = {117},
  article number = {D00U13},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856625229&doi=10.1029%2f2011JD016780&partnerID=40&md5=fe0cd2c01318bac34a354bfa4ed6385f},
  doi = {10.1029/2011JD016780}
}
Abstract: We have analysed the sensitivity of the tropospheric ozone distribution over North America and the North Atlantic to boreal biomass burning emissions during the summer of 2010 using the GEOS-Chem 3-D global tropospheric chemical transport model and observations from in situ and satellite instruments. We show that the model ozone distribution is consistent with observations from the Pico Mountain Observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES) and Infrared Atmospheric Sounding Instrument (IASI) satellite instruments. Mean biases between the model and observed ozone mixing ratio in the free troposphere were less than 10 ppbv. We used the adjoint of GEOS-Chem to show the model ozone distribution in the free troposphere over Maritime Canada is largely sensitive to NOx emissions from biomass burning sources in Central Canada, lightning sources in the central US, and anthropogenic sources in the eastern US and south-eastern Canada. We also used the adjoint of GEOS-Chem to evaluate the Fire Locating And Monitoring of Burning Emissions (FLAMBE) inventory through assimilation of CO observations from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. The CO inversion showed that, on average, the FLAMBE emissions needed to be reduced to 89% of their original values, with scaling factors ranging from 12% to 102%, to fit the MOPITT observations in the boreal regions. Applying the CO scaling factors to all species emitted from boreal biomass burning sources led to a decrease of the model tropospheric distributions of CO, PAN, and NOx by as much as -20 ppbv, -50 pptv, and -20 pptv respectively. The modification of the biomass burning emission estimates reduced the model ozone distribution by approximately -3 ppbv (-8%) and on average improved the agreement of the model ozone distribution compared to the observations throughout the free troposphere, reducing the mean model bias from 5.5 to 4.0 ppbv for the Pico Mountain Observatory, 3.0 to 0.9 ppbv for ozonesondes, 2.0 to 0.9 ppbv for TES, and 2.8 to 1.4 ppbv for IASI. © 2012 Author(s).
BibTeX:
@article{ParringtonPalmerHenzeEtAl2012,
  author = {Parrington, M. and Palmer, P.I. and Henze, D.K. and Tarasick, D.W. and Hyer, E.J. and Owen, R.C. and Helmig, D. and Clerbaux, C. and Bowman, K.W. and Deeter, M.N. and Barratt, E.M. and Coheur, P.-F. and Hurtmans, D. and Jiang, Z. and George, M. and Worden, J.R.},
  title = {The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {2077-2098},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860917357&doi=10.5194%2facp-12-2077-2012&partnerID=40&md5=e994ac464072358d7ff8be4bd707646f},
  doi = {10.5194/acp-12-2077-2012}
}
Abstract: Ozone data retrieved in the Arctic region from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI) on board the MetOp-A European satellite are presented. They are compared with in situ and lidar observations obtained during a series of aircraft measurement campaigns as part of the International Polar Year POLARCAT activities in spring and summer 2008. Different air masses were sampled during the campaigns including clean air, polluted plumes originating from anthropogenic sources, forest fire plumes from the three northern continents, and stratospheric-influenced air masses. The comparison between IASI O 3 [0-8 km], [0-12 km] partial columns and profiles with collocated aircraft observations is achieved by taking into account the different sensitivity and geometry of the sounding instruments. A detailed analysis is provided and the agreement is discussed in terms of vertical sensitivity and surface properties at the location of the observations. Overall, IASI O3 profiles are found to be in relatively good agreement with smoothed in situ and lidar profiles in the free troposphere with differences of less than 40% (25% over sea for both seasons) and 10%, respectively. The correlation between IASI O 3 retrieved partial columns and the smoothed aircraft partial columns is good with DC-8 in situ data in spring over North America (r= Combining double low line 0.68), and over Greenland with ATR-42 lidar measurements in summer (r= Combining double low line 0.67). Correlations with other data are less significant highlighting the difficulty of IASI to capture precisely the O 3 variability in the Arctic upper troposphere and lower stratosphere (UTLS). This is particularly noted in comparison with the [0-12 km] partial columns. The IASI [0-8 km] partial columns display a low negative bias (by less than 26% over snow) compared to columns derived from in situ measurements. Despite the relatively high biases of the IASI retrievals in the Arctic UTLS, our analysis shows that IASI can be used to identify, using O 3/CO ratios, stratospheric intrusions. © 2012 Author(s).
BibTeX:
@article{PommierClerbauxLawEtAl2012,
  author = {Pommier, M. and Clerbaux, C. and Law, K.S. and Ancellet, G. and Bernath, P. and Coheur, P.-F. and Hadji-Lazaro, J. and Hurtmans, D. and Nédélec, P. and Paris, J.-D. and Ravetta, F. and Ryerson, T.B. and Schlager, H. and Weinheimer, A.J.},
  title = {Analysis of IASI tropospheric O3 data over the Arctic during POLARCAT campaigns in 2008},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869016835&doi=10.5194%2facp-12-7371-2012&partnerID=40&md5=2772e2c879ad81d3c2304f688e119c08},
  doi = {10.5194/acp-12-7371-2012}
}
Abstract: In this study we have retrieved the self-broadened widths, self-pressure-induced shifts, and Dicke narrowing coefficients for 20 R-branch transitions in the v1+v2+v4+v5 band of acetylene. The spectra were recorded using a three-channel diode laser spectrometer, a temperature-controlled cell of fixed length and a second, room temperature cell. The soft collision (Galatry) and hard collision (Rautian) profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift, and Dicke narrowing coefficients. We performed comparisons between our retrieved line parameters and published line parameters for acetylene transitions. © 2012 Taylor and Francis.
BibTeX:
@article{PoveyPredoi-CrossHurtmans2012,
  author = {Povey, C. and Predoi-Cross, A. and Hurtmans, D.R.},
  title = {Low-pressure line shape study of acetylene transitions in the v1 + v2 + v4 + v5 band over a range of temperatures},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2633-2644},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872306703&doi=10.1080%2f00268976.2012.705908&partnerID=40&md5=5b0e6ecf5f42d3c1542a4ae82e5c89ec},
  doi = {10.1080/00268976.2012.705908}
}
Abstract: N2-broadened line widths and N2-pressure induced line shifts have been measured for transitions in the v1+v3 band of acetylene at seven temperatures in the range 213-333K to obtain the temperature dependences of broadening and shift coefficients. For the room-temperature spectra the line mixing effects have been also investigated. The Voigt and hard-collision line profile models were used to retrieve the line parameters. All spectra were recorded using a 3-channel tuneable diode laser spectrometer. The line-broadening and line-shifting coefficients as well as their temperature-dependence parameters have been also evaluated theoretically, in the frame of a semi-classical approach based on an exponential representation of the scattering operator, an intermolecular potential composed of electrostatic quadrupole-quadrupole and pairwise atom-atom interactions as well as on exact trajectories driven by an effective isotropic potential. © 2012 Taylor and Francis.
BibTeX:
@article{RozarioGarberPoveyEtAl2012,
  author = {Rozario, H. and Garber, J. and Povey, C. and Hurtmans, D. and Buldyreva, J. and Predoi-Cross, A.},
  title = {Experimental and theoretical study of N2-broadened acetylene line parameters in the v1+v3 band over a range of temperatures},
  journal = {Molecular Physics},
  year = {2012},
  volume = {110},
  pages = {2645-2663},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872351574&doi=10.1080%2f00268976.2012.720040&partnerID=40&md5=c093ed57741b38101e9c58b60639b1b7},
  doi = {10.1080/00268976.2012.720040}
}
Abstract: Measurements of ozone vertical profiles are valuable for the evaluation of atmospheric chemistry models and contribute to the understanding of the processes controlling the distribution of tropospheric ozone. The longest record of ozone vertical profiles is provided by ozone sondes, which have a typical frequency of 4 to 12 profiles a month. Here we quantify the uncertainty introduced by low frequency sampling in the determination of means and trends. To do this, the high frequency MOZAIC (Measurements of OZone, water vapor, carbon monoxide and nitrogen oxides by in-service AIrbus airCraft) profiles over airports, such as Frankfurt, have been subsampled at two typical ozone sonde frequencies of 4 and 12 profiles per month. We found the lowest sampling uncertainty on seasonal means at 700 hPa over Frankfurt, with around 5% for a frequency of 12 profiles per month and 10% for a 4 profile-a-month frequency. However the uncertainty can reach up to 15 and 29% at the lowest altitude levels. As a consequence, the sampling uncertainty at the lowest frequency could be higher than the typical 10% accuracy of the ozone sondes and should be carefully considered for observation comparison and model evaluation. We found that the 95% confidence limit on the seasonal mean derived from the subsample created is similar to the sampling uncertainty and suggest to use it as an estimate of the sampling uncertainty. Similar results are found at six other Northern Hemisphere sites. We show that the sampling substantially impacts on the inter-annual variability and the trend derived over the period 1998-2008 both in magnitude and in sign throughout the troposphere. Also, a tropical case is discussed using the MOZAIC profiles taken over Windhoek, Namibia between 2005 and 2008. For this site, we found that the sampling uncertainty in the free troposphere is around 8 and 12% at 12 and 4 profiles a month respectively. © 2012 Author(s).
BibTeX:
@article{SaunoisEmmonsLamarqueEtAl2012,
  author = {Saunois, M. and Emmons, L. and Lamarque, J.-F. and Tilmes, S. and Wespes, C. and Thouret, V. and Schultz, M.},
  title = {Impact of sampling frequency in the analysis of tropospheric ozone observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {6757-6773},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864624795&doi=10.5194%2facp-12-6757-2012&partnerID=40&md5=958e0a7ababd0ac0f259de56a5786443},
  doi = {10.5194/acp-12-6757-2012}
}
Abstract: In this paper we present a study of the ozone hole as observed by the Infrared Atmospheric Sounding Interferometer (IASI) on-board the MetOp-A European satellite platform from the beginning of data dissemination, August 2008, to the end of December 2010. Here we demonstrate IASI's ability to capture the seasonal characteristics of the ozone hole, in particular during polar night. We compare IASI ozone total columns and vertical profiles with those of the Global Ozone Monitoring Experiment 2 (GOME-2, also on-board MetOp-A) and electrochemical concentration cell (ECC) ozone sonde measurements. Total ozone column from IASI and GOME-2 were found to be in excellent agreement for this region with a correlation coefficient of 0.97, for September, October and November 2009. On average IASI exhibits a positive bias of approximately 7% compared to the GOME-2 measurements over the entire ozone hole period. Comparisons between IASI and ozone sonde measurements were also found to be in good agreement with the difference between both ozone profile measurements being less than ±30% over the altitude range of 0-40 km. The vertical structure of the ozone profile inside the ozone hole is captured remarkably well by IASI. © Author(s) 2012.
BibTeX:
@article{ScannellHurtmansBoynardEtAl2012,
  author = {Scannell, C. and Hurtmans, D. and Boynard, A. and Hadji-Lazaro, J. and George, M. and Delcloo, A. and Tuinder, O. and Coheur, P.-F. and Clerbaux, C.},
  title = {Antarctic ozone hole as observed by IASI/MetOp for 2008-2010},
  journal = {Atmospheric Measurement Techniques},
  year = {2012},
  volume = {5},
  pages = {123-139},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857713840&doi=10.5194%2famt-5-123-2012&partnerID=40&md5=308a3f2596ee503856d261ee388187cc},
  doi = {10.5194/amt-5-123-2012}
}
Abstract: Formic acid contributes significantly to acid rain in remote environments. Direct sources of formic acid include human activities, biomass burning and plant leaves. Aside from these direct sources, sunlight-induced oxidation of non-methane hydrocarbons (largely of biogenic origin) is probably the largest source. However, model simulations substantially underpredict atmospheric formic acid levels, indicating that not all sources have been included in the models. Here, we use satellite measurements of formic acid concentrations to constrain model simulations of the global formic acid budget. According to our simulations, 100- 120Tg of formic acid is produced annually, which is two to three times more than that estimated from known sources. We show that 90% of the formic acid produced is biogenic in origin, and largely sourced from tropical and boreal forests. We suggest that terpenoids- volatile organic compounds released by plants- are the predominant precursors. Model comparisons with independent observations of formic acid strengthen our conclusions, and provide indirect validation for the satellite measurements. Finally, we show that the larger formic acid emissions have a substantial impact on rainwater acidity, especially over boreal forests in the summer, where formic acid reduces pH by 0.25- 0.5.
BibTeX:
@article{StavrakouMuellerPeetersEtAl2012,
  author = {Stavrakou, T. and Müller, J.-F. and Peeters, J. and Razavi, A. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and De Mazière, M. and Vigouroux, C. and Deutscher, N.M. and Griffith, D.W.T. and Jones, N. and Paton-Walsh, C.},
  title = {Satellite evidence for a large source of formic acid from boreal and tropical forests},
  journal = {Nature Geoscience},
  year = {2012},
  volume = {5},
  pages = {26-30},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84255194908&doi=10.1038%2fngeo1354&partnerID=40&md5=d4f9be71850f471857979de27160e19a},
  doi = {10.1038/ngeo1354}
}
Abstract: Merapi volcano (Indonesia) is one of the most active and hazardous volcanoes in the world. It is known for frequent small to moderate eruptions, pyroclastic flows produced by lava dome collapse, and the large population settled on and around the flanks of the volcano that is at risk. Its usual behavior for the last decades abruptly changed in late October and early November 2010, when the volcano produced its largest and most explosive eruptions in more than a century, displacing at least a third of a million people, and claiming nearly 400 lives. Despite the challenges involved in forecasting this 'hundred year eruption', we show that the magnitude of precursory signals (seismicity, ground deformation, gas emissions) was proportional to the large size and intensity of the eruption. In addition and for the first time, near-real-time satellite radar imagery played an equal role with seismic, geodetic, and gas observations in monitoring eruptive activity during a major volcanic crisis. The Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) issued timely forecasts of the magnitude of the eruption phases, saving 10,000-20,000 lives. In addition to reporting on aspects of the crisis management, we report the first synthesis of scientific observations of the eruption. Our monitoring and petrologic data show that the 2010 eruption was fed by rapid ascent of magma from depths ranging from 5 to 30km. Magma reached the surface with variable gas content resulting in alternating explosive and rapid effusive eruptions, and released a total of ~0.44Tg of SO2. The eruptive behavior seems also related to the seismicity along a tectonic fault more than 40km from the volcano, highlighting both the complex stress pattern of the Merapi region of Java and the role of magmatic pressurization in activating regional faults. We suggest a dynamic triggering of the main explosions on 3 and 4 November by the passing seismic waves generated by regional earthquakes on these days. © 2012 Elsevier B.V.
BibTeX:
@article{SuronoJoussetPallisterEtAl2012,
  author = {Surono and Jousset, P. and Pallister, J. and Boichu, M. and Buongiorno, M.F. and Budisantoso, A. and Costa, F. and Andreastuti, S. and Prata, F. and Schneider, D. and Clarisse, L. and Humaida, H. and Sumarti, S. and Bignami, C. and Griswold, J. and Carn, S. and Oppenheimer, C. and Lavigne, F.},
  title = {The 2010 explosive eruption of Java's Merapi volcano-A '100-year' event},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2012},
  volume = {241-242},
  pages = {121-135},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866482387&doi=10.1016%2fj.jvolgeores.2012.06.018&partnerID=40&md5=148019b40c714c8b0bdd93cfec80e082},
  doi = {10.1016/j.jvolgeores.2012.06.018}
}
Abstract: The characterization and the precise measurements of atmospheric pollutant's concentration are essential to improve the understanding and modeling of urban air pollution processes. The QualAir platform at the Université Pierre et Marie Curie (UPMC) is an experimental research platform dedicated to urban air quality and pollution studies. As one of the major instruments, the ground-based QualAir Fourier transform spectrometer (FTS) provides information on the air composition of a megacity like Paris, France. Operating in solar infrared absorption, it enables the monitoring of several important pollutants involved in tropospheric chemistry and atmospheric transport around the Ile de France region. Results on nitrous oxide (N 2O), methane (CH 4), and carbon monoxide (CO) will be presented in this paper, as well as the CO measurements comparison with satellite and in situ measurements showing the capabilities and strengths of this groundbased FTS with the other instruments of the QualAir platform. © 2012 American Meteorological Society.
BibTeX:
@article{TeDieudonneJeseckEtAl2012,
  author = {Té, Y.V. and Dieudonné, E. and Jeseck, P. and Hase, F. and Hadji-Lazaro, J. and Clerbaux, C. and Ravetta, F. and Payan, S. and Pépin, I. and Hurtmans, D. and Pelon, J. and Camy-Peyret, C.},
  title = {Carbon monoxide urban emission monitoring: A ground-based FTIR case study},
  journal = {Journal of Atmospheric and Oceanic Technology},
  year = {2012},
  volume = {29},
  pages = {911-921},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84868261911&doi=10.1175%2fJTECH-D-11-00040.1&partnerID=40&md5=6efb8370a229405e330bf47ee5434b39},
  doi = {10.1175/JTECH-D-11-00040.1}
}
Abstract: The Eyjafjallajökull ash that crossed over Spain and Portugal on 6-12 May 2010 has been monitored by a set of operational sun photometer sites within AERONET-RIMA and satellite sensors. The sun photometer observations (aerosol optical depth, coarse mode concentrations) and ash products from IASI and SEVIRI satellite sensors, together with FLEXPART simulations of particle transport, allow identifying the volcanic aerosols. The aerosol columnar properties derived from inversions were investigated, indicating specific properties, especially regarding the absorption. The single scattering albedo was high (0.95 at 440nm) and nearly wavelength independent, although with slight decrease with wavelength. Other parameters, like the fine mode fraction of the volume size distributions (0.20-0.80) or the portion of spherical particles (15-90%), were very variable among the sites and indicated that the various ash clouds were inhomogeneous with respect to particle size and shape. © 2011 Elsevier Ltd.
BibTeX:
@article{ToledanoBennounaCachorroEtAl2012,
  author = {Toledano, C. and Bennouna, Y. and Cachorro, V. and Ortiz de Galisteo, J.P. and Stohl, A. and Stebel, K. and Kristiansen, N.I. and Olmo, F.J. and Lyamani, H. and Obregón, M.A. and Estellés, V. and Wagner, F. and Baldasano, J.M. and González-Castanedo, Y. and Clarisse, L. and de Frutos, A.M.},
  title = {Aerosol properties of the Eyjafjallajökull ash derived from sun photometer and satellite observations over the Iberian Peninsula},
  journal = {Atmospheric Environment},
  year = {2012},
  volume = {48},
  pages = {22-32},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855955189&doi=10.1016%2fj.atmosenv.2011.09.072&partnerID=40&md5=9025c90be338527a8280a0e93a5b0fb1},
  doi = {10.1016/j.atmosenv.2011.09.072}
}
Abstract: Methanol retrievals from nadir-viewing space-based sensors offer powerful new information for quantifying methanol emissions on a global scale. Here we apply an ensemble of aircraft observations over North America to evaluate new methanol measurements from the Tropospheric Emission Spectrometer (TES) on the Aura satellite, and combine the TES data with observations from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A satellite to investigate the seasonality of methanol emissions from northern midlatitude ecosystems. Using the GEOS-Chem chemical transport model as an intercomparison platform, we find that the TES retrieval performs well when the degrees of freedom for signal (DOFS) are above 0.5, in which case the model:TES regressions are generally consistent with the model:aircraft comparisons. Including retrievals with DOFS below 0.5 degrades the comparisons, as these are excessively influenced by the a priori. The comparisons suggest DOFS >0.5 as a minimum threshold for interpreting retrievals of trace gases with a weak tropospheric signal. We analyze one full year of satellite observations and find that GEOS-Chem, driven with MEGANv2.1 biogenic emissions, underestimates observed methanol concentrations throughout the midlatitudes in springtime, with the timing of the seasonal peak in model emissions 1-2 months too late. We attribute this discrepancy to an underestimate of emissions from new leaves in MEGAN, and apply the satellite data to better quantify the seasonal change in methanol emissions for midlatitude ecosystems. The derived parameters (relative emission factors of 11.0, 0.26, 0.12 and 3.0 for new, growing, mature, and old leaves, respectively, plus a leaf area index activity factor of 0.5 for expanding canopies with leaf area index <1.2) provide a more realistic simulation of seasonal methanol concentrations in midlatitudes on the basis of both the IASI and TES measurements. © 2012 Author(s).
BibTeX:
@article{WellsMilletHuEtAl2012,
  author = {Wells, K.C. and Millet, D.B. and Hu, L. and Cady-Pereira, K.E. and Xiao, Y. and Shephard, M.W. and Clerbaux, C.L. and Clarisse, L. and Coheur, P.-F. and Apel, E.C. and De Gouw, J. and Warneke, C. and Singh, H.B. and Goldstein, A.H. and Sive, B.C.},
  title = {Tropospheric methanol observations from space: Retrieval evaluation and constraints on the seasonality of biogenic emissions},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {5897-5912},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863908469&doi=10.5194%2facp-12-5897-2012&partnerID=40&md5=fa9a3a8aebfba5d8d9b282c892db7216},
  doi = {10.5194/acp-12-5897-2012}
}
Abstract: In this paper, we analyze tropospheric O3 together with HNO 3 during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) program, combining observations and model results. Aircraft observations from the NASA ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) and NOAA ARCPAC (Aerosol, Radiation and Cloud Processes affecting Arctic Climate) campaigns during spring and summer of 2008 are used together with the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) to assist in the interpretation of the observations in terms of the source attribution and transport of O 3 and HNO 3 into the Arctic (north of 60°N). The MOZART-4 simulations reproduce the aircraft observations generally well (within 15%), but some discrepancies in the model are identified and discussed. The observed correlation of O3 with HNO 3 is exploited to evaluate the MOZART-4 model performance for different air mass types (fresh plumes, free troposphere and stratospheric-contaminated air masses). Based on model simulations of O 3 and HNO 3 tagged by source type and region, we find that the anthropogenic pollution from the Northern Hemisphere is the dominant source of O 3 and HNO 3 in the Arctic at pressures greater than 400 hPa, and that the stratospheric influence is the principal contribution at pressures less 400 hPa. During the summer, intense Russian fire emissions contribute some amount to the tropospheric columns of both gases over the American sector of the Arctic. North American fire emissions (California and Canada) also show an important impact on tropospheric ozone in the Arctic boundary layer. Additional analysis of tropospheric O 3 measurements from ground-based FTIR and from the IASI satellite sounder made at the Eureka (Canada) and Thule (Greenland) polar sites during POLARCAT has been performed using the tagged contributions. It demonstrates the capability of these instruments for observing pollution at northern high latitudes. Differences between contributions from the sources to the tropospheric columns as measured by FTIR and IASI are discussed in terms of vertical sensitivity associated with these instruments. The first analysis of O 3 tropospheric columns observed by the IASI satellite instrument over the Arctic is also provided. Despite its limited vertical sensitivity in the lowermost atmospheric layers, we demonstrate that IASI is capable of detecting low-altitude pollution transported into the Arctic with some limitations. © 2012 Author(s).
BibTeX:
@article{WespesEmmonsEdwardsEtAl2012,
  author = {Wespes, C. and Emmons, L. and Edwards, D.P. and Hannigan, J. and Hurtmans, D. and Saunois, M. and Coheur, P.-F. and Clerbaux, C. and Coffey, M.T. and Batchelor, R.L. and Lindenmaier, R. and Strong, K. and Weinheimer, A.J. and Nowak, J.B. and Ryerson, T.B. and Crounse, J.D. and Wennberg, P.O.},
  title = {Analysis of ozone and nitric acid in spring and summer Arctic pollution using aircraft, ground-based, satellite observations and MOZART-4 model: Source attribution and partitioning},
  journal = {Atmospheric Chemistry and Physics},
  year = {2012},
  volume = {12},
  pages = {237-259},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855512617&doi=10.5194%2facp-12-237-2012&partnerID=40&md5=b72b8edf6b594eee45d275439fd71c32},
  doi = {10.5194/acp-12-237-2012}
}
Abstract: One of the most important atmospheric composition products derived from the first EUMETSAT Meteorological Operational satellite (MetOp-A) is the total ozone column (TOC). For this purpose, MetOp-A has two instruments on board: the Global Ozone Monitoring Experiment 2 (GOME-2) that retrieves the TOC data from the backscattered solar ultraviolet-visible (UV-Vis) radiance, and the Infrared Atmospheric Sounding Interferometer (IASI) that uses the thermal infrared radiance to derive TOC data. This paper focuses on the simultaneous validation of the TOC data provided by these two MetOp-A instruments using the measurements recorded by five well-calibrated Brewer UV spectrophotometers located at the Iberian Peninsula during the complete 2009. The results show an excellent correlation between the ground-based data and the GOME-2 and IASI satellite observations (R2 higher than 0.91). Differences between the ground-based and satellite TOC data show that the IASI instrument significantly overestimates the Brewer measurements (about 4.4% when all five ground-based stations are jointly used). In contrast, the GOME-2 instrument shows a slight underestimation (~1.6%). In addition, the absolute relative differences between the Brewer and GOME-2 data are quite smaller (about a factor higher than 2) than the Brewer-IASI absolute differences. The satellite viewing geometry (solar zenith angle and the view zenith angle) has no significant influence on the Brewer-satellite relative differences. Moreover, the analysis of these relative differences with respect to the ground-based TOC data indicates that GOME-2 instrument presents a slight underestimation for high TOC values. Finally, the IASI-GOME-2 correlation is high (R2~0.92), but with a mean relative difference of about ±6% which could be associated with the bias between UV-Vis and infrared spectroscopy used in the retrieval processes. © 2011 Elsevier Inc.
BibTeX:
@article{AntonLoyolaClerbauxEtAl2011,
  author = {Antón, M. and Loyola, D. and Clerbaux, C. and López, M. and Vilaplana, J.M. and Bañón, M. and Hadji-Lazaro, J. and Valks, P. and Hao, N. and Zimmer, W. and Coheur, P.F. and Hurtmans, D. and Alados-Arboledas, L.},
  title = {Validation of the MetOp-A total ozone data from GOME-2 and IASI using reference ground-based measurements at the Iberian Peninsula},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  pages = {1380-1386},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953228017&doi=10.1016%2fj.rse.2011.01.018&partnerID=40&md5=505063ce36166e8c43a6dd84da6db6ba},
  doi = {10.1016/j.rse.2011.01.018}
}
Abstract: Hydrogen sulphide (H2S) is one of the main trace gases released from volcanoes with yearly global emissions estimated between 1 and 37 Tg. With sulfur dioxide (SO2, 15-21 Tg/year), it dominates the volcanic sulfur budget, and the emission ratio H2S:SO2 is an important geochemical probe for studying source conditions, sulfur chemistry and magma-water interactions. Contrary to SO2, measurements of H 2S are sparse and difficult. Here we report the first measurements of a large H2S plume from space. Observations were made with the infrared sounder IASI of the volcanic plume released after the 7-8 August 2008 eruption of Kasatochi volcano. The eruption was characterized by 5 consecutive explosive events. The first events were phreatomagmatic producing a plume rich in water vapor and poor in ash and SO2. We show that the observed H2S plume, calculated at 29±10 kT with integrated columns exceeding 140±25 Dobson Units (DU), is likely associated with these first explosions. H2S:SO2 ratios with maximum values of 12±2 are found, representative of redox conditions in the hydrothermal envelop. With a detection threshold of 25 DU, future space observations of H2S plumes are certain. These will be important for improving the atmospheric sulfur budget and characterizing the H2S:SO2 fingerprint of different eruptions. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{ClarisseCoheurChefdevilleEtAl2011,
  author = {Clarisse, L. and Coheur, P.-F. and Chefdeville, S. and Lacour, J.-L. and Hurtmans, D. and Clerbaux, C.},
  title = {Infrared satellite observations of hydrogen sulfide in the volcanic plume of the August 2008 Kasatochi eruption},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L10804},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957933501&doi=10.1029%2f2011GL047402&partnerID=40&md5=e5b97545f3d5af5ea07ba653be9d43d5},
  doi = {10.1029/2011GL047402}
}
Abstract: Using 3 years worth of IASI (the Infrared Atmospheric Sounder Interferometer aboard METOP-A) measurements, we have identified 24 major events of uplift and transport of anthropogenic sulfur dioxide. These were all first observed over East Asia, and could be traced for over 60 hours. On 7 November 2010 a sulfur dioxide plume was observed over Northeast China and tracked for five days to North America. We discuss this event in detail with respect to build up; uplift and in-plume chemistry. We found a host of trace gas enhancements in the plume (SO2, CO, PAN, CH3OH, HCOOH and C2H2). A reasonable to very good agreement was found with MOZART-4 modeled ambient columns for all species except methanol, which was underestimated by the model by an order of magnitude. We calculate correlations of the different species and give observational evidence of secondary in-plume formation of methanol and PAN. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{ClarisseFrommNgadiEtAl2011,
  author = {Clarisse, L. and Fromm, M. and Ngadi, Y. and Emmons, L. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.},
  title = {Intercontinental transport of anthropogenic sulfur dioxide and other pollutants: An infrared remote sensing case study},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L19806},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054772582&doi=10.1029%2f2011GL048976&partnerID=40&md5=374959a5dec5c8f5f4c07e0991077e19},
  doi = {10.1029/2011GL048976}
}
Abstract: [1] Thermal infrared nadir sounders are ideal for observing total columns or vertical profiles of atmospheric gases such as water, carbon dioxide and ozone. High resolution sounders with a spectral resolution below 5 cm -1 can distinguish fine spectral features of trace gases. Forty years after the launch of the first hyperspectral sounder IRIS, we have now several state of the art instruments in orbit, with improved instrumental specifications. In this letter we give an overview of the trace gases which have been observed by infrared nadir sounders, focusing on new observations of the Infrared Atmospheric Sounding Interferometer (IASI). We present typical observations of 14 rare reactive trace gas species. Several species are reported here for the first time in nadir view, including nitrous acid, furan, acetylene, propylene, acetic acid, formaldehyde and hydrogen cyanide, observations which were made in a pyrocumulus cloud from the Australian bush fires of February 2009. Being able to observe this large number of reactive trace gases will likely improve our knowledge of source emissions and their impact on the environment and climate.
BibTeX:
@article{ClarisseRHoniCoheurEtAl2011,
  author = {Clarisse, L. and R'Honi, Y. and Coheur, P.-F. and Hurtmans, D. and Clerbaux, C.},
  title = {Thermal infrared nadir observations of 24 atmospheric gases},
  journal = {Geophysical Research Letters},
  year = {2011},
  volume = {38},
  article number = {L10802},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054720716&doi=10.1029%2f2011GL047271&partnerID=40&md5=feb3663c3f4c1ecd92b6d25258eb1acb},
  doi = {10.1029/2011GL047271}
}
Abstract: We evaluate climatologies of upper tropospheric ozone and nitric acid retrieved from two satellite instruments (ACE-FTS and OSIRIS) with long-term in situ measurements from aircraft (MOZAIC, CR-AVE, PRE-AVE, PEM Tropics, and TC4) and ozonesondes. A global chemical transport model (GEOS-Chem) is used to guide the evaluation and to relate sparse in situ measurements with the satellite retrievals. Both satellite retrievals generally reproduce broad ozone features in the upper troposphere such as summer enhancements in the northern subtropics and larger concentrations over the tropical Atlantic versus the tropical Pacific. These comparisons indicate biases in annual, tropical mean ozone concentrations from both ACE-FTS (10-13%) and OSIRIS (5%) relative to aircraft and ozonesonde observations. More uncertain evidence suggests that nitric acid from ACE-FTS has a positive mean bias of 15%. We demonstrate that an upper limit on the ozone production efficiency in the upper troposphere can be determined using ACE-FTS satellite measurements of O3 and HNO3. The resulting value of 196 (+34, -61) mol/mol is in broad agreement with model simulations. Higher OPE values inferred from ACE-FTS over the tropical Pacific (249 (+21, -68) mol/mol) than the tropical Atlantic (146 (+16, -41) mol/mol) reflect increasing ozone production efficiency with decreasing pollution. This analysis indicates a new capability of satellite observations to provide insight into ozone production in the tropical troposphere. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{CooperMartinSauvageEtAl2011,
  author = {Cooper, M. and Martin, R.V. and Sauvage, B. and Boone, C.D. and Walker, K.A. and Bernath, P.F. and McLinden, C.A. and Degenstein, D.A. and Volz-Thomas, A. and Wespes, C.},
  title = {Evaluation of ACE-FTS and OSIRIS Satellite retrievals of ozone and nitric acid in the tropical upper troposphere: Application to ozone production efficiency},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D12306},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960081989&doi=10.1029%2f2010JD015056&partnerID=40&md5=c4372e10ec9981602b281b6ff1a8afeb},
  doi = {10.1029/2010JD015056}
}
Abstract: The Eyjafjallajökull volcano in Iceland erupted explosively on 14 April 2010, emitting a plume of ash into the atmosphere. The ash was transported from Iceland toward Europe where mostly cloud-free skies allowed ground-based lidars at Chilbolton in England and Leipzig in Germany to estimate the mass concentration in the ash cloud as it passed overhead. The UK Met Office's Numerical Atmospheric-dispersion Modeling Environment (NAME) has been used to simulate the evolution of the ash cloud from the Eyjafjallajökull volcano during the initial phase of the ash emissions, 14-16 April 2010. NAME captures the timing and sloped structure of the ash layer observed over Leipzig, close to the central axis of the ash cloud. Relatively small errors in the ash cloud position, probably caused by the cumulative effect of errors in the driving meteorology en route, result in a timing error at distances far from the central axis of the ash cloud. Taking the timing error into account, NAME is able to capture the sloped ash layer over the UK. Comparison of the lidar observations and NAME simulations has allowed an estimation of the plume height time series to be made. It is necessary to include in the model input the large variations in plume height in order to accurately predict the ash cloud structure at long range. Quantitative comparison with the mass concentrations at Leipzig and Chilbolton suggest that around 3% of the total emitted mass is transported as far as these sites by small (<100 μm diameter) ash particles. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{DacreGrantHoganEtAl2011,
  author = {Dacre, H.F. and Grant, A.L.M. and Hogan, R.J. and Belcher, S.E. and Thomson, D.J. and Devenish, B.J. and Marenco, F. and Hort, M.C. and Haywood, J.M. and Ansmann, A. and Mattis, I. and Clarisse, L.},
  title = {Evaluating the structure and magnitude of the ash plume during the initial phase of the 2010 Eyjafjallajökull eruption using lidar observations and NAME simulations},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D00U03},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960899888&doi=10.1029%2f2011JD015608&partnerID=40&md5=1c690786a173cd5f5c30dd832b5e1a51},
  doi = {10.1029/2011JD015608}
}
Abstract: The Measurements of Pollution in the Troposphere (MOPITT) retrievals are used as top-down constraints in an inversion for global CO emissions, for the past 10 years (from March 2000 to December 2009), at 8 day and 3.75° × 2.75° (longitude, latitude) resolution. The method updates a standard prior inventory and yields large increments in terms of annual regional budgets and seasonality. Our validation strategy consists in comparing our posterior-modeled concentrations with several sets of independent measurements: surface measurements, aircraft, and satellite. The posterior emissions, with a global 10 year average of 1430 TgCO/yr, are 37% higher than the prior ones, built from the EDGAR 3.2 and the GFEDv2 inventories (1038 TgCO/yr on average). In addition, they present some significant seasonal variations in the Northern Hemisphere that are not present in our prior nor in others' major inventories. Our results also exhibit some large interannual variability due to biomass burning emissions, climate, and socioeconomic factors; CO emissions range from 1504 TgCO (in 2007) to 1318 TgCO (in 2009). Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{Fortems-CheineyChevallierPisonEtAl2011,
  author = {Fortems-Cheiney, A. and Chevallier, F. and Pison, I. and Bousquet, P. and Szopa, S. and Deeter, M.N. and Clerbaux, C.},
  title = {Ten years of CO emissions as seen from Measurements of Pollution in the Troposphere (MOPITT)},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2011},
  volume = {116},
  article number = {D05304},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952767866&doi=10.1029%2f2010JD014416&partnerID=40&md5=14d97bc988d71653ba2f08c3c19187c7},
  doi = {10.1029/2010JD014416}
}
Abstract: The atmosphere-ocean general circulation models (AOGCMs) used for the IPCC 4th Assessment Report (IPCC AR4) are evaluated for the Greenland ice sheet (GrIS) current climate modelling. The most suited AOGCMs for Greenland climate simulation are then selected on the basis of comparison between the 1970-1999 outputs of the Climate of the twentieth Century experiment (20C3M) and reanalyses (ECMWF, NCEP/NCAR). This comparison indicates that the representation quality of surface parameters such as temperature and precipitation are highly correlated to the atmospheric circulation (500 hPa geopotential height) and its interannual variability (North Atlantic oscillation). The outputs of the three most suitable AOGCMs for present-day climate simulation are then used to assess the changes estimated by three IPCC greenhouse gas emissions scenarios (SRES) over the GrIS for the 2070-2099 period. Future atmospheric circulation changes are projected to dampen the zonal flow, enhance the meridional fluxes and therefore provide additional heat and moisture to the GrIS, increasing temperature over the whole ice sheet and precipitation over its northeastern area. We also show that the GrIS surface mass balance anomalies from the SRES A1B scenario amount to -300 km3/year with respect to the 1970-1999 period, leading to a global sea-level rise of 5 cm by the end of the 21st century. This work can help to select the boundaries conditions for AOGCMs-based downscaled future projections. © 2010 Springer-Verlag.
BibTeX:
@article{FrancoFettweisErpicumEtAl2011,
  author = {Franco, B. and Fettweis, X. and Erpicum, M. and Nicolay, S.},
  title = {Present and future climates of the Greenland ice sheet according to the IPCC AR4 models},
  journal = {Climate Dynamics},
  year = {2011},
  volume = {36},
  pages = {1897-1918},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79954494231&doi=10.1007%2fs00382-010-0779-1&partnerID=40&md5=b022e924acfbbabf7ad6fb488511eff9},
  doi = {10.1007/s00382-010-0779-1}
}
Abstract: We report measurements of self- and nitrogen-pressure broadening of the P(11) line in the ν1 + ν3 combination band of acetylene at 195 739.649 5135(80) GHz by absorption of radiation emitted by an extended cavity diode laser referenced to a femtosecond frequency comb. Broadening, shift and narrowing parameters were determined at 296 K. For the most appropriate, hard collision, model in units of cm-1/atm, we find 0.146317(27), 0.047271(104) and -0.0070819(22) for the acetylene self-broadening, narrowing and shift, and 0.081129(35), 0.022940(74) and -0.0088913(25) respectively, for the nitrogen-broadening parameters. The uncertainties are expressed as one standard deviation (in parenthesis) in units of the last digit reported. These parameters are 2-3 orders of magnitude more precise than those reported in previous measurements. Similar analyses of the experimental data using soft collision and simple Voigt lineshape models were made for comparison. © 2011 Elsevier Inc. All rights reserved.
BibTeX:
@article{McRavenCichLopezEtAl2011,
  author = {McRaven, C.P. and Cich, M.J. and Lopez, G.V. and Sears, T.J. and Hurtmans, D. and Mantz, A.W.},
  title = {Frequency comb-referenced measurements of self- and nitrogen-broadening in the ν1 + ν3 band of acetylene},
  journal = {Journal of Molecular Spectroscopy},
  year = {2011},
  volume = {266},
  pages = {43-51},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953800320&doi=10.1016%2fj.jms.2011.02.016&partnerID=40&md5=80ac4d689a432574adae8922559ec6ad},
  doi = {10.1016/j.jms.2011.02.016}
}
Abstract: In this study we have retrieved the line intensities, self broadened widths, pressure-induced shifts and selected line mixing coefficients for 20 R-branch transitions in the ν1 + ν2 + ν4 + ν5 band of acetylene. The spectra were recorded using our 3-channels diode laser spectrometer, a temperature controlled cell of fixed length and a second, room temperature cell. The Voigt and speed-dependent Voigt profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift and line mixing coefficients. © 2011 Elsevier Inc. All rights reserved.
BibTeX:
@article{PoveyPredoi-CrossHurtmans2011,
  author = {Povey, C. and Predoi-Cross, A. and Hurtmans, D.R.},
  title = {Line shape study of acetylene transitions in the ν1 + ν2 + ν4 + ν5 band over a range of temperatures},
  journal = {Journal of Molecular Spectroscopy},
  year = {2011},
  volume = {268},
  pages = {177-188},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052266912&doi=10.1016%2fj.jms.2011.04.020&partnerID=40&md5=218ced30e33acefbdbdf526795130e50},
  doi = {10.1016/j.jms.2011.04.020}
}
Abstract: Methanol (CH3OH) and formic acid (HCOOH) are among the most abundant volatile organic compounds present in the atmosphere. In this work, we derive the global distributions of these two organic species using for the first time the Infrared Atmospheric Sounding Interferometer (IASI) launched onboard the MetOp-A satellite in 2006. This paper describes the method used and provides a first critical analysis of the retrieved products. The retrieval process follows a two-step approach in which global distributions are first obtained on the basis of a simple radiance indexing (transformed into brightness temperatures), and then mapped onto column abundances using suitable conversion factors. For methanol, the factors were calculated using a complete retrieval approach in selected regions. In the case of formic acid, a different approach, which uses a set of forward simulations for representative atmospheres, has been used. In both cases, the main error sources are carefully determined: the average relative error on the column for both species is estimated to be about 50%, increasing to about 100% for the least favorable conditions. The distributions for the year 2009 are discussed in terms of seasonality and source identification. Time series comparing methanol, formic acid and carbon monoxide in different regions are also presented. © 2011 Author(s).
BibTeX:
@article{RazaviKaragulianClarisseEtAl2011,
  author = {Razavi, A. and Karagulian, F. and Clarisse, L. and Hurtmans, D. and Coheur, P.F. and Clerbaux, C. and Müller, J.F. and Stavrakou, T.},
  title = {Global distributions of methanol and formic acid retrieved for the first time from the IASI/MetOp thermal infrared sounder},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {857-872},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79551527999&doi=10.5194%2facp-11-857-2011&partnerID=40&md5=21c3966374ff3d945a54a0303a955e50},
  doi = {10.5194/acp-11-857-2011}
}
Abstract: Presently only limited sets of tropospheric ammonia (NH3) measurements in the Earth's atmosphere have been reported from satellite and surface station measurements, despite the well-documented negative impact of NH3 on the environment and human health. Presented here is a detailed description of the satellite retrieval strategy and analysis for the Tropospheric Emission Spectrometer (TES) using simulations and measurements. These results show that: (i) the level of detectability for a representative boundary layer TES NH3 mixing ratio value is ∼0.4 ppbv, which typically corresponds to a profile that contains a maximum level value of ∼1 ppbv; (ii) TES NH3 retrievals generally provide at most one degree of freedom for signal (DOFS), with peak sensitivity between 700 and 900 mbar; (iii) TES NH3 retrievals show significant spatial and seasonal variability of NH3 globally; (iv) initial comparisons of TES observations with GEOS-CHEM estimates show TES values being higher overall. Important differences and similarities between modeled and observed seasonal and spatial trends are noted, with discrepancies indicating areas where the timing and magnitude of modeled NH3 emissions from agricultural sources, and to lesser extent biomass burning sources, need further study. © Author(s) 2011. CC Attribution 3.0 License.
BibTeX:
@article{ShephardCady-PereiraLuoEtAl2011,
  author = {Shephard, M.W. and Cady-Pereira, K.E. and Luo, M. and Henze, D.K. and Pinder, R.W. and Walker, J.T. and Rinsland, C.P. and Bash, J.O. and Zhu, L. and Payne, V.H. and Clarisse, L.},
  title = {TES ammonia retrieval strategy and global observations of the spatial and seasonal variability of ammonia},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {10743-10763},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80155202960&doi=10.5194%2facp-11-10743-2011&partnerID=40&md5=41ed3c3f1764348ba2afab8a3242dee9},
  doi = {10.5194/acp-11-10743-2011}
}
Abstract: During the POLARCAT summer campaign in 2008, two episodes (2g-5 July and 7g-10 July 2008) occurred where low-pressure systems traveled from Siberia across the Arctic Ocean towards the North Pole. The two cyclones had extensive smoke plumes from Siberian forest fires and anthropogenic sources in East Asia embedded in their associated air masses, creating an excellent opportunity to use satellite and aircraft observations to validate the performance of atmospheric transport models in the Arctic, which is a challenging model domain due to numerical and other complications. Here we compare transport simulations of carbon monoxide (CO) from the Lagrangian transport model FLEXPART and the Eulerian chemical transport model TOMCAT with retrievals of total column CO from the IASI passive infrared sensor onboard the MetOp-A satellite. The main aspect of the comparison is how realistic horizontal and vertical structures are represented in the model simulations. Analysis of CALIPSO lidar curtains and in situ aircraft measurements provide further independent reference points to assess how reliable the model simulations are and what the main limitations are. The horizontal structure of mid-latitude pollution plumes agrees well between the IASI total column CO and the model simulations. However, finer-scale structures are too quickly diffused in the Eulerian model. Applying the IASI averaging kernels to the model data is essential for a meaningful comparison. Using aircraft data as a reference suggests that the satellite data are biased high, while TOMCAT is biased low. FLEXPART fits the aircraft data rather well, but due to added background concentrations the simulation is not independent from observations. The multi-data, multi-model approach allows separating the influences of meteorological fields, model realisation, and grid type on the plume structure. In addition to the very good agreement between simulated and observed total column CO fields, the results also highlight the difficulty to identify a data set that most realistically represents the actual pollution state of the Arctic atmosphere. © 2011 Adis Data Information BV. All rights reserved.
BibTeX:
@article{SodemannPommierArnoldEtAl2011,
  author = {Sodemann, H. and Pommier, M. and Arnold, S.R. and Monks, S.A. and Stebel, K. and Burkhart, J.F. and Hair, J.W. and Diskin, G.S. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Schlager, H. and Blechschmidt, A.-M. and Kristjánsson, J.E. and Stohl, A.},
  title = {Episodes of cross-polar transport in the Arctic troposphere during July 2008 as seen from models, satellite, and aircraft observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {3631-3651},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79954991383&doi=10.5194%2facp-11-3631-2011&partnerID=40&md5=5afbc20efcca79dbf04be8bb85ea8672},
  doi = {10.5194/acp-11-3631-2011}
}
Abstract: This study provides improved methanol emission estimates on the global scale, in particular for the largest methanol source, the terrestrial biosphere, and for biomass burning. To this purpose, one complete year of spaceborne measurements of tropospheric methanol columns retrieved for the first time by the thermal infrared sensor IASI aboard the MetOp satellite are compared with distributions calculated by the IMAGESv2 global chemistry-transport model. Two model simulations are performed using a priori biogenic methanol emissions either from the new MEGANv2.1 emission model, which is fully described in this work and is based on net ecosystem flux measurements, or from a previous parameterization based on net primary production by Jacob et al. (2005). A significantly better model performance in terms of both amplitude and seasonality is achieved through the use of MEGANv2.1 in most world regions, with respect to IASI data, and to surface- and air-based methanol measurements, even though important discrepancies over several regions are still present. As a second step of this study, we combine the MEGANv2.1 and the IASI column abundances over continents in an inverse modelling scheme based on the adjoint of the IMAGESv2 model to generate an improved global methanol emission source. The global optimized source totals 187 Tg yr&minus;1 with a contribution of 100 Tg yr&minus;1 from plants, only slightly lower than the a priori MEGANv2.1 value of 105 Tg yr&minus;1. Large decreases with respect to the MEGANv2.1 biogenic source are inferred over Amazonia (up to 55 %) and Indonesia (up to 58 %), whereas more moderate reductions are recorded in the Eastern US (20-25 %) and Central Africa (25-35 %). On the other hand, the biogenic source is found to strongly increase in the arid and semi-arid regions of Central Asia (up to a factor of 5) and Western US (factor of 2), probably due to a source of methanol specific to these ecosystems which is unaccounted for in the MEGANv2.1 inventory. The most significant error reductions achieved by the optimization concern the derived biogenic emissions over the Amazon and over the Former Soviet Union. The robustness of the derived fluxes to changes in convective updraft fluxes, in methanol removal processes, and in the choice of the biogenic a priori inventory is assessed through sensitivity inversions. Detailed comparisons of the model with a number of aircraft and surface observations of methanol, as well as new methanol measurements in Europe and in the Reunion Island show that the satellite-derived methanol emissions improve significantly the agreement with the independent data, giving thus credence to the IASI dataset. © 2011 Author(s).
BibTeX:
@article{StavrakouGuentherRazaviEtAl2011,
  author = {Stavrakou, T. and Guenther, A. and Razavi, A. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Karagulian, F. and De MaziÃ̈re, M. and Vigouroux, C. and Amelynck, C. and Schoon, N. and Laffineur, Q. and Heinesch, B. and Aubinet, M. and Rinsland, C. and Müller, J.-F.},
  title = {First space-based derivation of the global atmospheric methanol emission fluxes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {4873-4898},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957817767&doi=10.5194%2facp-11-4873-2011&partnerID=40&md5=c2ad094fe0aa3b54aa07d62154f57884},
  doi = {10.5194/acp-11-4873-2011}
}
Abstract: The Aprilg-May, 2010 volcanic eruptions of Eyjafjallajökull, Iceland caused significant economic and social disruption in Europe whilst state of the art measurements and ash dispersion forecasts were heavily criticized by the aviation industry. Here we demonstrate for the first time that large improvements can be made in quantitative predictions of the fate of volcanic ash emissions, by using an inversion scheme that couples a priori source information and the output of a Lagrangian dispersion model with satellite data to estimate the volcanic ash source strength as a function of altitude and time. From the inversion, we obtain a total fine ash emission of the eruption of 8.3 ± 4.2 Tg for particles in the size range of 2.8g-28 μm diameter. We evaluate the results of our model results with a posteriori ash emissions using independent ground-based, airborne and space-borne measurements both in case studies and statistically. Subsequently, we estimate the area over Europe affected by volcanic ash above certain concentration thresholds relevant for the aviation industry. We find that during three episodes in April and May, volcanic ash concentrations at some altitude in the atmosphere exceeded the limits for the "Normal" flying zone in up to 14 % (6g-16 %), 2 % (1g-3 %) and 7 % (4g-11 %), respectively, of the European area. For a limit of 2 mg mĝ̂'3 only two episodes with fractions of 1.5 % (0.2g-2.8 %) and 0.9 % (0.1g-1.6 %) occurred, while the current "No-Fly" zone criterion of 4 mg mg-3 was rarely exceeded. Our results have important ramifications for determining air space closures and for real-time quantitative estimations of ash concentrations. Furthermore, the general nature of our method yields better constraints on the distribution and fate of volcanic ash in the Earth system. © 2011 Author(s).
BibTeX:
@article{StohlPrataEckhardtEtAl2011,
  author = {Stohl, A. and Prata, A.J. and Eckhardt, S. and Clarisse, L. and Durant, A. and Henne, S. and Kristiansen, N.I. and Minikin, A. and Schumann, U. and Seibert, P. and Stebel, K. and Thomas, H.E. and Thorsteinsson, T. and Tørseth, K. and Weinzierl, B.},
  title = {Determination of time-and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: The 2010 Eyjafjallajökull eruption},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {4333-4351},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955921544&doi=10.5194%2facp-11-4333-2011&partnerID=40&md5=2112a81a293824d94356ab55d4c3ba5a},
  doi = {10.5194/acp-11-4333-2011}
}
Abstract: To further our understanding of the effects of biomass burning emissions on atmospheric composition, we report measurements of trace species in biomass burning plumes made by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) instrument on the SCISAT-1 satellite. An extensive set of 15 molecules, C 2H 2, C 2H 6, CH 3OH, CH 4, CO, H 2CO, HCN, HCOOH, HNO 3, NO, NO 2, N 2O 5, O 3, OCS and SF6 are used in our analysis. Even though most biomass burning smoke is typically confined to the boundary layer, some of these emissions are injected directly into the free troposphere via fire-related convective processes and transported away from the emission source. Further knowledge of the aging of biomass burning emissions in the free troposphere is needed. Tracer-tracer correlations are made between known pyrogenic species in these plumes in an effort to characterize them and follow their chemical evolution. Criteria such as age and type of biomass material burned are considered. © 2011 Author(s).
BibTeX:
@article{TereszchukGonzalezAbadClerbauxEtAl2011,
  author = {Tereszchuk, K.A. and González Abad, G. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F. and Bernath, P.F.},
  title = {ACE-FTS measurements of trace species in the characterization of biomass burning plumes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2011},
  volume = {11},
  pages = {12169-12179},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-83455247379&doi=10.5194%2facp-11-12169-2011&partnerID=40&md5=f8868b2503227bf7b258de70dcdb9c4f},
  doi = {10.5194/acp-11-12169-2011}
}
Abstract: We present a new method for measuring SO2 with the data from the ASTER (Advanced Spaceborne Thermal Emission and Reflectance radiometer) orbital sensor. The method consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations. We present a sensitivity analysis for this method, and two case studies. The sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity, sulfate aerosols, surface altitude and emissivity than the raw radiances. Measurements with &lt;25% relative precision are achieved, but only when the thermal contrast between the plume and the underlying surface is higher than 10K. For the case studies we focused on Miyakejima and Etna, two volcanoes where SO2 is measured regularly by COSPEC or scanning DOAS. The SO2 fluxes computed from a series of ten images of Miyakejima over the period 2000-2002 is in agreement with the long term trend of measurement for this volcano. On Etna, we compared SO2 column amounts measured by ASTER with those acquired simultaneously by ground-based automated scanning DOAS. The column amounts compare quite well, providing a more rigorous validation of the method. The SO2 maps retrieved with ASTER can provide quantitative insights into the 2D structure of non-eruptive volcanic plumes, their dispersion and their progressive depletion in SO2. © 2010 .
BibTeX:
@article{CampionSalernoCoheurEtAl2010,
  author = {Campion, R. and Salerno, G.G. and Coheur, P.-F. and Hurtmans, D. and Clarisse, L. and Kazahaya, K. and Burton, M. and Caltabiano, T. and Clerbaux, C. and Bernard, A.},
  title = {Measuring volcanic degassing of SO2 in the lower troposphere with ASTER band ratios},
  journal = {Journal of Volcanology and Geothermal Research},
  year = {2010},
  volume = {194},
  pages = {42-54},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953695330&doi=10.1016%2fj.jvolgeores.2010.04.010&partnerID=40&md5=d32eb0e829bb77a6979040a68ee042ee},
  doi = {10.1016/j.jvolgeores.2010.04.010}
}
Abstract: We present a sophisticated radiative transfer code for modeling outgoing IR radiation from planetary atmospheres and, conversely, for retrieving atmospheric properties from high-resolution nadir-observed spectra. The forward model is built around a doubling-adding routine and calculates, in a spherical refractive geometry, the outgoing radiation emitted by the Earth and the atmosphere containing one layer of aerosol. The inverse model uses an optimal estimation approach and can simultaneously retrieve atmospheric trace gases, aerosol effective radius, and concentration. It is different from existing codes, as most forward codes dealing with multiple scattering assume a plane-parallel atmosphere, and as for the retrieval, it does not rely on precalculated spectra, the use of microwindows, or two-step retrievals. The simultaneous retrieval on a broad spectral range exploits the full potential of current state-of-the-art hyperspectral IR sounders, such as AIRS and IASI, and should be particularly useful in studying major pollution events. We present five example retrievals of IASI spectra observed in the range from 800 to 1200 cm-1 above dust, volcanic ash, sulfuric acid, ice particles, and biomass burning aerosols. © 2010 Optical Society of America.
BibTeX:
@article{ClarisseHurtmansPrataEtAl2010,
  author = {Clarisse, L. and Hurtmans, D. and Prata, A.J. and Karagulian, F. and Clerbaux, C. and De Mazière, M. and Coheur, P.-F.},
  title = {Retrieving radius, concentration, optical depth, and mass of different types of aerosols from high-resolution infrared nadir spectra},
  journal = {Applied Optics},
  year = {2010},
  volume = {49},
  pages = {3713-3722},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955955085&doi=10.1364%2fAO.49.003713&partnerID=40&md5=4c20760101f604d10b70ad715ff1c8ef},
  doi = {10.1364/AO.49.003713}
}
Abstract: Remote satellite detection of airborne volcanic ash is important for mitigating hazards to aviation and for calculating plume altitudes. Infrared sounders are essential for detecting ash, as they can distinguishing aerosol type and can be used day and night. While broadband sensors are mainly used for this purpose, they have inherent limitations. Typically, water and ice can mask volcanic ash, while wind blown dust can yield false detection. High spectral resolution sounders should be able to overcome some of these limitations. However, existing detection methods are not easily applicable to hyperspectral sounders and there is therefore a pressing need for novel techniques. In response, we propose a sensitive and robust volcanic ash detection method for hyperspectral sounders based on correlation coefficients and demonstrate it on IASI observations. We show that the method differentiates ash from clouds and dust. Easy to implement, it could contribute to operational volcanic hazard mitigation. © 2010 by the American Geophysical Union.
BibTeX:
@article{ClarissePrataLacourEtAl2010,
  author = {Clarisse, L. and Prata, F. and Lacour, J.-L. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.},
  title = {A correlation method for volcanic ash detection using hyperspectral infrared measurements},
  journal = {Geophysical Research Letters},
  year = {2010},
  volume = {37},
  article number = {L19806},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958033389&doi=10.1029%2f2010GL044828&partnerID=40&md5=a3f8d9e75ea66b402b3d501cc0af96fb},
  doi = {10.1029/2010GL044828}
}
Abstract: [1] Atmospheric ammonia (NH3) has recently been observed with infrared sounders from space. Here we present 1 year of detailed bidaily satellite retrievals with the Infrared Atmospheric Sounding Interferometer and some retrievals of the Tropospheric Emission Spectrometer over the San Joaquin Valley, California, a highly polluted agricultural production region. Several sensitivity issues are discussed related to the sounding of ammonia, in terms of degrees of freedom, averaging kernels, and altitude of maximum sensitivity and in relation to thermal contrast and concentration. We also discuss their seasonal dependence and sources of errors. We demonstrate boundary layer sensitivity of infrared sounders when there is a large thermal contrast between the surface and the bottom of the atmosphere. For the San Joaquin Valley, large thermal contrast is the case for daytime measurements in spring, summer, and autumn and for nighttime measurements in autumn and winter when a large negative thermal contrast is amplified by temperature inversion. © 2010 by the American Geophysical Union.
BibTeX:
@article{ClarisseShephardDentenerEtAl2010,
  author = {Clarisse, L. and Shephard, M.W. and Dentener, F. and Hurtmans, D. and Cady-Pereira, K. and Karagulian, F. and Van Damme, M. and Clerbaux, C. and Coheur, P.-F.},
  title = {Satellite monitoring of ammonia: A case study of the San Joaquin Valley},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D13302},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956048077&doi=10.1029%2f2009JD013291&partnerID=40&md5=171bd371827597f5be0cafc472109219},
  doi = {10.1029/2009JD013291}
}
Abstract: Atmospheric remote sensing from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. During this decade, remote sensors using the thermal infrared (TIR) spectral range have demonstrated their ability to sound the troposphere and provide global distribution for some of the key atmospheric species. This article illustrates three operational applications made possible with the IASI instrument onboard the European satellite MetOp, which opens new perspectives for routine observation of the evolution of atmospheric composition from space. © 2009 Académie des sciences.
BibTeX:
@article{ClerbauxTurquetyCoheur2010,
  author = {Clerbaux, C. and Turquety, S. and Coheur, P.},
  title = {Infrared remote sensing of atmospheric composition and air quality: Towards operational applications},
  journal = {Comptes Rendus - Geoscience},
  year = {2010},
  volume = {342},
  pages = {349-356},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77951623751&doi=10.1016%2fj.crte.2009.09.010&partnerID=40&md5=d17ec8059a24db6e55d00d193b2b0830},
  doi = {10.1016/j.crte.2009.09.010}
}
Abstract: High-spectral resolution infrared spectra of the earth's atmosphere and surface are routinely available from satellite sensors, such as the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI). We exploit the spectral content of AIRS data to demonstrate that airborne volcanic ash has a unique signature in the infrared (8-12 μm) that can be used to infer particle size, infrared opacity and composition. The spectral signature is interpreted with the aid of a radiative transfer model utilizing the optical properties of andesite, rhyolite and quartz. Based on the infrared spectral signature, a new volcanic ash detection algorithm is proposed that can discriminate volcanic ash from other airborne substances and we show that the algorithm depends on particle size, optical depth and composition. The new algorithm has an improved sensitivity to optically thin ash clouds, and hence can detect them for longer (~ 4 days) and at greater distances from the source(~ 5000 km). © 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{GangalePrataClarisse2010,
  author = {Gangale, G. and Prata, A.J. and Clarisse, L.},
  title = {The infrared spectral signature of volcanic ash determined from high-spectral resolution satellite measurements},
  journal = {Remote Sensing of Environment},
  year = {2010},
  volume = {114},
  pages = {414-425},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-71349087092&doi=10.1016%2fj.rse.2009.09.007&partnerID=40&md5=a68ecbe3ae45d2c882ae9a82dd6d6483},
  doi = {10.1016/j.rse.2009.09.007}
}
Abstract: In June 2009 the Sarychev volcano located in the Kuril Islands to the northeast of Japan erupted explosively, injecting ash and an estimated 1.2 0.2 Tg of sulfur dioxide into the upper troposphere and lower stratosphere, making it arguably one of the 10 largest stratospheric injections in the last 50 years. During the period immediately after the eruption, we show that the sulfur dioxide (SO2) cloud was clearly detected by retrievals developed for the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument and that the resultant stratospheric sulfate aerosol was detected by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and CALIPSO lidar. Additional surface-based instrumentation allows assessment of the impact of the eruption on the stratospheric aerosol optical depth. We use a nudged version of the HadGEM2 climate model to investigate how well this state-of-the-science climate model can replicate the distributions of SO 2 and sulfate aerosol. The model simulations and OSIRIS measurements suggest that in the Northern Hemisphere the stratospheric aerosol optical depth was enhanced by around a factor of 3 (0.01 at 550 nm), with resultant impacts upon the radiation budget. The simulations indicate that, in the Northern Hemisphere for July 2009, the magnitude of the mean radiative impact from the volcanic aerosols is more than 60% of the direct radiative forcing of all anthropogenic aerosols put together. While the cooling induced by the eruption will likely not be detectable in the observational record, the combination of modeling and measurements would provide an ideal framework for simulating future larger volcanic eruptions. Copyright 2010 by the American Geophysical Union.
BibTeX:
@article{HaywoodJonesClarisseEtAl2010,
  author = {Haywood, J.M. and Jones, A. and Clarisse, L. and Bourassa, A. and Barnes, J. and Telford, P. and Bellouin, N. and Boucher, O. and Agnew, P. and Clerbaux, C. and Coheur, P. and Degenstein, D. and Braesicke, P.},
  title = {Observations of the eruption of the Sarychev volcano and simulations using the HadGEM2 climate model},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D21212},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649260983&doi=10.1029%2f2010JD014447&partnerID=40&md5=8637d1a3d6237289ac8259ad718b85c2},
  doi = {10.1029/2010JD014447}
}
Abstract: In this work we use infrared spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI) to characterize the emissions from the Mount Kasatochi volcanic eruption on 7 and 8 August 2008. We first derive the total atmospheric load of sulfur dioxide (SO2) and its evolution over time. For the initial plume, we found values over 1.7 Tg Of SO2, making it the largest eruption since the 1991 eruptions of Pinatubo and Hudson. Vertical profiles were retrieved using a line-by-line radiative transfer model and an inversion procedure based on the optimal estimation method (OEM). For the Kasatochi eruption, we found a plume altitude of 12.5 ± 4 km. Taking advantage of IASI's broad spectral coverage, we used the v3 band (∼ 1362 cm-1) and, for the first time, the v1 + v 3 band (∼2500 cm-1) of SO2 for the retrievals. While the v3 band saturates easily for high SO 2 concentrations, preventing accurate retrieval, the v1 + v3 band has a much higher saturation threshold. We also analyzed the broadband signature observed in the radiance spectra in the 1072-1215 cm -1 range associated with the presence of aerosols. In the initial volcanic plume the signature matches closely that of mineral ash, while by 10 August most mineral ash is undetectable, and the extinction is shown to match closely the absorption spectrum of liquid H2SO4 drops. The extinction by sulphuric acid particles was confirmed by comparing spectra before and a month after the eruption, providing the first spectral detection of such aerosols from nadir view radiance data. Copyright 2010 by the American Geophysical Union.
BibTeX:
@article{KaragulianClarisseClerbauxEtAl2010,
  author = {Karagulian, F. and Clarisse, L. and Clerbaux, C. and Prata, A.J. and Hurtmans, D. and Coheur, P.F.},
  title = {Detection of volcanic SO2, ash, and H2SO4 using the infrared atmospheric sounding interferometer (IASI)},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D00L02},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855179975&doi=10.1029%2f2009JD012786&partnerID=40&md5=7e956486b36a25ee9a06b81b16331226},
  doi = {10.1029/2009JD012786}
}
BibTeX:
@article{KeimEremenkoOrphalEtAl2010,
  author = {Keim, C. and Eremenko, M. and Orphal, J. and Dufour, G. and Flaud, J.-M. and Höpfner, M. and Boynard, A. and Clerbaux, C. and Payan, S. and Coheur, P.-F. and Hurtmans, D. and Claude, H. and De Backer, H. and Dier, H. and Johnson, B. and Kelder, H. and Kivi, R. and Koide, T. and López Bartolomé, M. and Lambkin, K. and Moore, D. and Schmidlin, F.J. and Stübi, R.},
  title = {Erratum: Tropospheric ozone from IASI: Comparison of different inversion algorithms and validation with ozone sondes in the northern middle latitudes (Atmospheric Chemistry and Physics (2009) 9 (9329-9347) DOI: 10.5194/acp-9-9329-2009)},
  journal = {Atmospheric Chemistry and Physics},
  year = {2010},
  volume = {10},
  pages = {6345},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954584493&doi=10.5194%2facp-10-6345-2010&partnerID=40&md5=21acb7c2686a515f6ec06023de39381e},
  doi = {10.5194/acp-10-6345-2010}
}
Abstract: In this paper, we provide a detailed comparison between carbon monoxide (CO) data measured by the Infrared Atmospheric Sounding Interferometer (IASI)/MetOp and aircraft observations over the Arctic. The CO measurements were obtained during North American (NASA ARCTAS and NOAA ARCPAC) and European campaigns (POLARCAT-France, POLARCAT-GRACE and YAK-AEROSIB) as part of the International Polar Year (IPY) POLARCAT activity in spring and summer 2008. During the campaigns different air masses were sampled including clean air, polluted plumes originating from anthropogenic sources in Europe, Asia and North America, and forest fire plumes originating from Siberia and Canada. The paper illustrates that CO-rich plumes following different transport pathways were well captured by the IASI instrument, in particular due to the high spatial coverage of IASI. The comparison between IASI CO total columns, 0ĝ€"5 km partial columns and profiles with collocated aircraft data was achieved by taking into account the different sensitivity and geometry of the sounding instruments. A detailed analysis is provided and the agreement is discussed in terms of information content and surface properties at the location of the observations. For profiles, the data were found to be in good agreement in spring with differences lower than 17%, whereas in summer the difference can reach 20% for IASI profiles below 8 km for polluted cases. For total columns the correlation coefficients ranged from 0.15 to 0.74 (from 0.47 to 0.77 for partial columns) in spring and from 0.26 to 0.84 (from 0.66 to 0.88 for partial columns) in summer. A better agreement is seen over the sea in spring (0.73 for total column and 0.78 for partial column) and over the land in summer (0.69 for total columns and 0.81 for partial columns). The IASI vertical sensitivity was better over land than over sea, and better over land than over sea ice and snow allowing a higher potential to detect CO vertical distribution during summer. © 2010 Author(s).
BibTeX:
@article{PommierLawClerbauxEtAl2010,
  author = {Pommier, M. and Law, K.S. and Clerbaux, C. and Turquety, S. and Hurtmans, D. and Hadji-Lazaro, J. and Coheur, P.-F. and Schlager, H. and Ancellet, G. and Paris, J.-D. and Néd́lec, P. and Diskin, G.S. and Podolske, J.R. and Holloway, J.S. and Bernath, P.},
  title = {IASI carbon monoxide validation over the Arctic during POLARCAT spring and summer campaigns},
  journal = {Atmospheric Chemistry and Physics},
  year = {2010},
  volume = {10},
  pages = {10655-10678},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78249288859&doi=10.5194%2facp-10-10655-2010&partnerID=40&md5=fc1de614df15de367192ea3c4a1cd2dd},
  doi = {10.5194/acp-10-10655-2010}
}
Abstract: Ash particles and sulfur dioxide gas are two significant components of volcanic clouds that are important because of their effects on the atmosphere. Several different satellite instruments are capable of delivering quantitative measurements of ash and SO2, but few can provide simultaneous assessments. High-spectral resolution (ν/Δν ∼ 1200) infrared satellite data from the Atmospheric Infrared Sounder (AIRS) are utilized to detect volcanic ash within the 8-12 μm window region, and at the same time exploit the 4.0 μm and 7.3 μm bands of SO2 to detect SO 2 at two different heights. The purpose is to study the interaction between gas and particles in dispersing volcanic clouds, and investigate the circumstances when the gas-rich and ash-rich parts of the plume are collocated and when they separate. Simultaneous retrievals of ash and SO2 in the eruption clouds from Okmok and Kasatochi suggest that the two components were transported together for at least the first 3 days after the initial injection. Later (several days) transport is difficult to infer because of the lack of sensitivity of the ash algorithm to thin, dispersing ash clouds. For Kasatochi and Okmok, AIRS measured maximum masses of approximately 1.21 ± 0.01 Tg and 0.29 ± 0.01 Tg of SO2, and 0.31 ± 0.03 Tg and 0.07 ±0.03 Tg of fine ash (1 μm < radii < 10 μm), respectively. The retrieval schemes described here are capable of detecting the distribution of SO2 simultaneously with estimates of ash concentrations from the same satellite instrument and represent an important improvement for observations of multispecies dispersing volcanic clouds. Analyses of other volcanic eruptions show that SO2 and ash do not always travel together. Consequently, it is concluded that for dispersing volcanic clouds it is vital to be able to detect both SO2-rich and ash-rich clouds simultaneously in order to diagnose their effect on the atmosphere and the aviation hazard. © 2010 by the American Geophysical Union.
BibTeX:
@article{PrataGangaleClarisseEtAl2010,
  author = {Prata, A.J. and Gangale, G. and Clarisse, L. and Karagulian, F.},
  title = {Ash and sulfur dioxide in the 2008 eruptions of Okmok and Kasatochi: Insights from high spectral resolution satellite measurements},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2010},
  volume = {115},
  article number = {D00L18},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955947801&doi=10.1029%2f2009JD013556&partnerID=40&md5=c867a7fa4baa6f7cc99e8deb5af11deb},
  doi = {10.1029/2009JD013556}
}
Abstract: Using a Fourier transform spectrometer setup we have measured the self-broadened half width, pressure shift, and line asymmetry coefficients for transitions in the 30012←00001 and 30013←00001 vibrational bands of carbon dioxide for four different temperatures. A total of 46 pure CO2 spectra were recorded at 0.008 and 0.009cm-1 resolution and at pressures varying from a few Torr to nearly an atmosphere. The individual spectral line profiles have been fitted by a Voigt profile and a speed-dependent Voigt profile, to which we have added dispersion profiles to account for weak line mixing. A comparison of the sets of results obtained for each band showed no vibrational dependence of the broadening coefficients. The self-broadening and self-shift coefficients are compared to semiclassical calculations based on the Robert-Bonamy formalism and were found to be in good agreement. The line asymmetry results are compared to line mixing calculations based on the Energy Corrected Sudden (ECS) and Exponential Power Gap models. © 2010 Elsevier Ltd.
BibTeX:
@article{Predoi-CrossLiuMurphyEtAl2010,
  author = {Predoi-Cross, A. and Liu, W. and Murphy, R. and Povey, C. and Gamache, R.R. and Laraia, A.L. and McKellar, A.R.W. and Hurtmans, D.R. and Malathy Devi, V.},
  title = {Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012←00001 and 30013←00001 bands},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2010},
  volume = {111},
  pages = {1065-1079},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77950933182&doi=10.1016%2fj.jqsrt.2010.01.003&partnerID=40&md5=ecee914fc2835758ce0f8b5e00227136},
  doi = {10.1016/j.jqsrt.2010.01.003}
}
Abstract: The variability and origin of the Coloured Dissolved Organic Matter (CDOM) were studied in the Belgian coastal and adjacent areas including offshore waters and the Scheldt estuary, through the parameters: absorption at 375 nm, aCDOM(375), and the slope of the absorption curve, S. aCDOM(375) varied between 0.20 and 1.31 m-1 and between 0.97 and 4.30 m-1 in the marine area and Scheldt estuary, respectively. S fluctuated between 0.0101 and 0.0203 nm-1 in the marine area and between 0.0167 and 0.0191 nm-1 in the Scheldt estuary. The comparative analysis of aCDOM(375) and S variations evidenced different origins of CDOM in the BCZ. The Scheldt estuarine waters showed decreasing aCDOM(375) values with increasing salinity but constant S value of ∼0.018 nm-1 suggesting a dominant terrestrial origin of CDOM. On the contrary, samples collected in the marine domain showed a narrow range of aCDOM(375) but highly variable S suggesting the additional presence of autochthonous sources of CDOM. This source was evidenced based on the sorting of the marine offshore data according to the stage of the phytoplankton bloom when they were collected. A clear distinction was made between CDOM released during the growth stage characterized by high S (∼0.017 nm-1) and low aCDOM(375) and the decay phase characterized by low S (∼0.013 nm-1) and high aCDOM(375). This observation was supported by CDOM measurements performed on pure phytoplankton cultures which showed increased CDOM release along the wax and wane of the bloom but decreasing S. We concluded that the high variability of the CDOM signature in offshore waters is explained by the local biological production and processing of CDOM. © 2009 Elsevier Ltd. All rights reserved.
BibTeX:
@article{AstorecaRousseauLancelot2009,
  author = {Astoreca, R. and Rousseau, V. and Lancelot, C.},
  title = {Coloured dissolved organic matter (CDOM) in Southern North Sea waters: Optical characterization and possible origin},
  journal = {Estuarine, Coastal and Shelf Science},
  year = {2009},
  volume = {85},
  pages = {633-640},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70449527354&doi=10.1016%2fj.ecss.2009.10.010&partnerID=40&md5=7611ed2562edfe0f7d25460beb58e5d4},
  doi = {10.1016/j.ecss.2009.10.010}
}
Abstract: While mapping algal blooms from space is now well-established, mapping undesirable algal blooms in eutrophicated coastal waters raises further challenge in detecting individual phytoplankton species. In this paper, an algorithm is developed and tested for detecting Phaeocystis globosa blooms in the Southern North Sea. For this purpose, we first measured the light absorption properties of two phytoplankton groups, P. globosa and diatoms, in laboratory-controlled experiments. The main spectral difference between both groups was observed at 467 nm due to the absorption of the pigment chlorophyll c3 only present in P. globosa, suggesting that the absorption at 467 nm can be used to detect this alga in the field. A Phaeocystis-detection algorithm is proposed to retrieve chlorophyll c3 using either total absorption or water-leaving reflectance field data. Application of this algorithm to absorption and reflectance data from Phaeocystis-dominated natural communities shows positive results. Comparison with pigment concentrations and cell counts suggests that the algorithm can flag the presence of P. globosa and provide quantitative information above a chlorophyll c3 threshold of 0.3 mg m -3 equivalent to a P. globosa cell density of 3 × 10 6 cells L-1. Finally, the possibility of extrapolating this information to remote sensing reflectance data in these turbid waters is evaluated. © 2008 The Author(s).
BibTeX:
@article{AstorecaRousseauRuddickEtAl2009,
  author = {Astoreca, R. and Rousseau, V. and Ruddick, K. and Knechciak, C. and Van Mol, B. and Parent, J.-Y. and Lancelot, C.},
  title = {Development and application of an algorithm for detecting Phaeocystis globosa blooms in the Case 2 Southern North Sea waters},
  journal = {Journal of Plankton Research},
  year = {2009},
  volume = {31},
  pages = {287-300},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-59849097655&doi=10.1093%2fplankt%2ffbn116&partnerID=40&md5=c3ccaf7afce5b2e6401f32eeaa9abf71},
  doi = {10.1093/plankt/fbn116}
}
Abstract: In this paper, we present measurements of total and tropospheric ozone, retrieved from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI), which was launched on board the MetOp-A European satellite in October 2006. We compare IASI total ozone columns to Global Ozone Monitoring Experiment-2 (GOME-2) observations and groundbased measurements from the Dobson and Brewer network for one full year of observations (2008). The IASI total ozone columns are shown to be in good agreement with both GOME-2 and ground-based data, with correlation coefficients of about 0.9 and 0.85, respectively. On average, IASI ozone retrievals exhibit a positive bias of about 9DU (3.3%) compared to both GOME-2 and ground-based measurements. In addition to total ozone columns, the good spectral resolution of IASI enables the retrieval of tropospheric ozone concentrations. Comparisons of IASI tropospheric columns to 490 collocated ozone soundings available from several stations around the globe have been performed for the period of June 2007-August 2008. IASI tropospheric ozone columns compare well with sonde observations, with correlation coefficients of 0.95 and 0.77 for the [surface-6 km] and [surface-12 km] partial columns, respectively. IASI retrievals tend to overestimate the tropospheric ozone columns in comparison with ozonesonde measurements. Positive average biases of 0.15DU (1.2%) and 3DU (11%) are found for the [surface-6 km] and for the [surface-12 km] partial columns respectively. © 2009 Author(s).
BibTeX:
@article{BoynardClerbauxCoheurEtAl2009,
  author = {Boynard, A. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Turquety, S. and George, M. and Hadji-Lazaro, J. and Keim, C. and Meyer-Arnek, J.},
  title = {Measurements of total and tropospheric ozone from IASI: Comparison with correlative satellite, ground-based and ozonesonde observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {6255-6271},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051996495&doi=10.5194%2facp-9-6255-2009&partnerID=40&md5=4fc546344408b81e037ec3cdc463c9c2},
  doi = {10.5194/acp-9-6255-2009}
}
Abstract: Global ammonia emissions have more than doubled since pre-industrial times, largely owing to agricultural intensification and widespread fertilizer use1. In the atmosphere, ammonia accelerates particulate matter formation, thereby reducing air quality. When deposited in nitrogen-limited ecosystems, ammonia can act as a fertilizer. This can lead to biodiversity reductions in terrestrial ecosystems, and algal blooms in aqueous environments2-8. Despite its ecological significance, there are large uncertainties in the magnitude of ammonia emissions, mainly owing to a paucity of ground-based observations and a virtual absence of atmospheric measurements3,8-11. Here we use infrared spectra, obtained by the IASI/MetOp satellite, to map global ammonia concentrations from space over the course of 2008. We identify several ammonia hotspots in middle-low latitudes across the globe. In general, we find a good qualitative agreement between our satellite measurements and simulations made using a global atmospheric chemistry transport model. However, the satellite data reveal substantially higher concentrations of ammonia north of 30° N, compared with model projections. We conclude that ammonia emissions could have been significantly underestimated in the Northern Hemisphere, and suggest that satellite monitoring of ammonia from space will improve our understanding of the global nitrogen cycle. © 2009 Macmillan Publishers Limited. All rights reserved.
BibTeX:
@article{ClarisseClerbauxDentenerEtAl2009,
  author = {Clarisse, L. and Clerbaux, C. and Dentener, F. and Hurtmans, D. and Coheur, P.-F.},
  title = {Global ammonia distribution derived from infrared satellite observations},
  journal = {Nature Geoscience},
  year = {2009},
  volume = {2},
  pages = {479-483},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68149171748&doi=10.1038%2fngeo551&partnerID=40&md5=5675beb45787291cb70f0d5a34da8563},
  doi = {10.1038/ngeo551}
}
Abstract: Atmospheric remote sounding from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. The IASI nadir looking thermal infrared sounder onboard MetOp will provide 15 years of global scale observations for a series of key atmospheric species, with unprecedented spatial sampling and coverage. This paper gives an overview of the instrument's capability for measuring atmospheric composition in the perspective of chemistry and air quality. The assessment is made in terms of species, accuracy and vertical information. Global distributions are presented for CO, CH4, O3 (total and tropospheric), HNO3, NH3, and volcanic SO2. Local distributions of organic species measured during fire events, such as C2H4, CH3OH, HCOOH, and PAN are also shown. For each species or process, the link is made to specialized papers in this issue. © 2009 Author(s).
BibTeX:
@article{ClerbauxBoynardClarisseEtAl2009,
  author = {Clerbaux, C. and Boynard, A. and Clarisse, L. and George, M. and Hadji-Lazaro, J. and Herbin, H. and Hurtmans, D. and Pommier, M. and Razavi, A. and Turquety, S. and Wespes, C. and Coheur, P.-F.},
  title = {Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {6041-6054},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051988004&doi=10.5194%2facp-9-6041-2009&partnerID=40&md5=45f0d0a23c73902e7172b425b490640e},
  doi = {10.5194/acp-9-6041-2009}
}
Abstract: This work presents observations of a series of short-lived species in biomass burning plumes from the Infrared Atmospheric Sounding Interferometer (IASI), launched onboard the MetOp-A platform in October 2006. The strong fires that have occurred in the Mediterranean Basin - and particularly Greece - in August 2007, and those in Southern Siberia and Eastern Mongolia in the early spring of 2008 are selected to support the analyses. We show that the IASI infrared spectra in these fire plumes contain distinctive signatures of ammonia (NH3), ethene (C2H4), methanol (CH 3OH) and formic acid (HCOOH) in the atmospheric window between 800 and 1200 cm-1, with some noticeable differences between the plumes. Peroxyacetyl nitrate (CH3COOONO2, abbreviated as PAN) was also observed with good confidence in some plumes and a tentative assignment of a broadband absorption spectral feature to acetic acid (CH3COOH) is made. For several of these species these are the first reported measurements made from space in nadir geometry. The IASI measurements are analyzed for plume height and concentration distributions of NH3, C2H 4 and CH3OH. The Greek fires are studied in greater detail for the days associated with the largest emissions. In addition to providing information on the spatial extent of the plume, the IASI retrievals allow an estimate of the total mass emissions for NH3, C2H 4 and CH3OH. Enhancement ratios are calculated for the latter relative to carbon monoxide (CO), giving insight in the chemical processes occurring during the transport, the first day after the emission.
BibTeX:
@article{CoheurClarisseTurquetyEtAl2009,
  author = {Coheur, P.-F. and Clarisse, L. and Turquety, S. and Hurtmans, D. and Clerbaux, C.},
  title = {IASI measurements of reactive trace species in biomass burning plumes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {5655-5667},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68149094692&doi=10.5194%2facp-9-5655-2009&partnerID=40&md5=b9acc48cd51bc04bd4f374e29ec1f1b6},
  doi = {10.5194/acp-9-5655-2009}
}
Abstract: Between July and November 2008, simultaneous observations were conducted by several orbiting instruments that monitor carbon monoxide in the atmosphere, among them the Infrared Atmospheric Sounding Instrument (IASI) and Measurements Of Pollution In The Troposphere (MOPITT). In this paper, the concentration retrievals at about 700 hPa from these two instruments are successively used in a variational Bayesian system to infer the global distribution of CO emissions. Starting from a global emission budget of 479 Tg for the considered period, the posterior estimate of CO emissions using IASI retrievals gives a total of 643 Tg, which is in close agreement with the budget calculated with version 3 of the MOPITT data (649 Tg). The regional totals are also broadly consistent between the two inversions. Even though our theoretical error budget indicates that IASI constrains the emissions slightly less than MOPITT, because of lesser sensitivity in the lower troposphere, these first results indicate that IASI may play a major role in the quantification of the emissions of CO.
BibTeX:
@article{Fortems-CheineyChevallierPisonEtAl2009,
  author = {Fortems-Cheiney, A. and Chevallier, F. and Pison, I. and Bousquet, P. and Carouge, C. and Clerbaux, C. and Coheur, P.-F. and George, M. and Hurtmans, D. and Szopa, S.},
  title = {On the capability of IASI measurements to inform about CO surface emissions},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {8735-8743},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70450257534&doi=10.5194%2facp-9-8735-2009&partnerID=40&md5=4bc37fc9d7337ee4d229ca4a2c745290},
  doi = {10.5194/acp-9-8735-2009}
}
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp satellite measures carbon monoxide (CO) on a global scale, twice a day. CO total columns and vertical profiles are retrieved in near real time from the nadir radiance spectra measured by the instrument in the thermal infrared (TIR) spectral range. This paper describes the measurement vertical sensitivity and provides a first assessment of the capabilities of IASI to measure CO distributions. On the global scale, 0.8 to 2.4 independent pieces of information are available for the retrieval. At mid latitudes, the information ranges between 1.5 and 2, which enables the lower and upper troposphere to be distinguished, especially when thermal contrast is significant. Global distributions of column CO are evaluated with correlative observations available from other nadir looking TIR missions currently in operation: the Measurements of Pollution in the Troposphere (MOPITT) onboard TERRA, the Atmospheric Infrared Sounder (AIRS) onboard AQUA and the Tropospheric Emission Spectrometer (TES) onboard AURA. The IASI CO columns are compared with MOPITT, AIRS and TES CO columns, adjusted with the a priori, for three different months: August 2008, November 2008 and February 2009. On average, total column discrepancies of about 7% are found between IASI and the three other sounders in the Northern Hemisphere and in the equatorial region. However when strong CO concentrations are present, such as during fire events, these discrepancies can climb as high as 17%. Instrument specifications of IASI versus other missions are also discussed.
BibTeX:
@article{GeorgeClerbauxHurtmansEtAl2009,
  author = {George, M. and Clerbaux, C. and Hurtmans, D. and Turquety, S. and Coheur, P.-F. and Pommier, M. and Hadji-Lazaro, J. and Edwards, D.P. and Worden, H. and Luo, M. and Rinsland, C. and McMillan, W.},
  title = {Carbon monoxide distributions from the IASI/METOP mission: Evaluation with other space-borne remote sensors},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {8317-8330},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70450259333&doi=10.5194%2facp-9-8317-2009&partnerID=40&md5=199427d10c9fb03aa678152793843e68},
  doi = {10.5194/acp-9-8317-2009}
}
Abstract: This work reports the first measurements of ethene (C2H 4) distributions in the upper troposphere. These are obtained by retrieving vertical profiles from 5 to 20 km infrared solar occultation spectra recorded in 2005 and 2006 by the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS). Background volume mixing ratios (vmrs) ranging from a few to about 50 pptv (10-12) are measured at the different altitudes, while for certain occultations, vmrs as high as 200 pptv are observed. Zonal distributions and vertically resolved latitudinal distributions are derived for the two year period analyzed, highlighting spatial -including a North-South gradient- as well as seasonal variations. We show the latter to be more pronounced at the highest latitudes, presumably as a result less active photochemistry during winter. The observation of C2H4 enhancements in remote Arctic regions at high latitudes is consistent with the occurrence fast transport processes of gaseous pollution from the continents leading to Arctic haze. © 2009.
BibTeX:
@article{HerbinHurtmansClarisseEtAl2009,
  author = {Herbin, H. and Hurtmans, D. and Clarisse, L. and Turquety, S. and Clerbaux, C. and Rinsland, C.P. and Boone, C. and Bernath, P.F. and Coheur, P.-F.},
  title = {Distributions and seasonal variations of tropospheric ethene (C 2H4) from Atmospheric Chemistry Experiment (ACE-FTS) solar occupation spectra},
  journal = {Geophysical Research Letters},
  year = {2009},
  volume = {36},
  article number = {L04801},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-66149160511&doi=10.1029%2f2008GL036338&partnerID=40&md5=d79b49a36d7c9d1f770569bfd4bb26c1},
  doi = {10.1029/2008GL036338}
}
Abstract: In this paper we analyze distributions of water vapour isotopologues in the troposphere using infrared spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI), which operates onboard the Metop satellite in nadir geometry. The simultaneous uncorrelated retrievals of H2 16O and HDO are performed on radiance measurements using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM). The characterizations of the retrieved products in terms of vertical sensitivity and error budgets show that IASI measurements contain up to 6 independent pieces of information on the vertical distribution of H216O and up to 3.5 for HDO from the surface up to the upper troposphere (0-20 km). Although the purpose of the paper is not validation, a restricted comparison with sonde measurements shows that the retrieved H216O profiles capture the seasonal/latitudinal variations of the water content, with good accuracy in the lowest layer but with larger uncertainties higher in the free and upper troposphere. Our results then demonstrate the ability of the IASI instrument to monitor atmospheric isotopologic water vapour distributions and to provide information on the partitioning of HDO as compared to H216O. The derivation of the δD is challenging and associated with large errors in the uncorrelated retrieval approach chosen here. As a result averaging on the vertical to produce a column-averaged δD is required to produce meaningful results for geophysical interpretation. As a case study, we analyse concentration distributions and spatio-temporal variations of H2 16O and δD during the October 2007 Krosa super-typhoon over South-East Asia. We show that individual δD have uncertainties of 37&amp;permil; for the vertically averaged values. Using the latter, we suggest that the typhoon produces a so-called amount-effect, where the δD is negatively correlated to the water amounts as a result of intense depletion of the deuterated species.
BibTeX:
@article{HerbinHurtmansClerbauxEtAl2009,
  author = {Herbin, H. and Hurtmans, D. and Clerbaux, C. and Clarisse, L. and Coheur, P.-F.},
  title = {H216O and HDO measurements with IASI/MetOp},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {9433-9447},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70549103454&partnerID=40&md5=a9aceff01982c13d1a6c75a4c582f038}
}
Abstract: High resolution measurements of room temperature absorption with a controlled tunable diode laser (TDL) spectrometer have been made for R(2) and P(14) lines in the HCl fundamental band perturbed by N2, Xe, Ar and He at pressures lower than one atmosphere. Pressure broadening, shift and collisional narrowing parameters have been extracted by least-squares fitting of several collisional profiles to the spectra. Asymmetries are observed for P(14) broadened by Xe at the lowest pressures and attributed to correlations between velocity- and phase-changing collisions. © 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{HurtmansHenryValentinEtAl2009,
  author = {Hurtmans, D. and Henry, A. and Valentin, A. and Boulet, C.},
  title = {Narrowing broadening and shifting parameters for R(2) and P(14) lines in the HCl fundamental band perturbed by N2 and rare gases from tunable diode laser spectroscopy},
  journal = {Journal of Molecular Spectroscopy},
  year = {2009},
  volume = {254},
  pages = {126-136},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-61849125820&doi=10.1016%2fj.jms.2009.01.015&partnerID=40&md5=a1d9667c3edf3782f0d41a9c7ecd7be9},
  doi = {10.1016/j.jms.2009.01.015}
}
Abstract: In the northern Gulf of Eilat (Aqaba), sharp increases in the biomass of diatoms and rates of primary production occurred in April 2008. Within 24 h, diatom abundance rose from 8 Ã- 103 to 228 Ã- 10 3 cells l-1, and photosynthetic rates concomitantly doubled from 15 to 35 μg C l-1 d-1. Water transparency declined, as indicated by the vertical diffusion attenuation coefficient K d for photosynthetically active radiation (PAR), which increased from 0.076 to 0.090 m-1 and decreased the euphotic depth from 60 to 45 m. During this time, a significant increase in silica deposition by the diatoms was also detected. We attribute the mentioned changes in environmental characteristics to wind-generated surface currents. Strong winds (up to 10 m s-1) during the measurements enriched the surface layers with unusually high nutrient concentrations within.
BibTeX:
@article{IluzDishonCapuzzoEtAl2009,
  author = {Iluz, D. and Dishon, G. and Capuzzo, E. and Meeder, E. and Astoreca, R. and Montecino, V. and Znachor, P. and Ediger, D. and Marra, J.},
  title = {Short-term variability in primary productivity during a wind-driven diatom bloom in the Gulf of Eilat (Aqaba)},
  journal = {Aquatic Microbial Ecology},
  year = {2009},
  volume = {56},
  pages = {205-215},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349188497&doi=10.3354%2fame01321&partnerID=40&md5=aca71db0ed72d28e24fdffbb10e5d27b},
  doi = {10.3354/ame01321}
}
Abstract: This paper presents a first statistical validation of tropospheric ozone products derived from measurements of the IASI satellite instrument. Since the end of 2006, IASI (Infrared Atmospheric Sounding Interferometer) aboard the polar orbiter Metop-A measures infrared spectra of the Earth's atmosphere in nadir geometry. This validation covers the northern mid-latitudes and the period from July 2007 to August 2008. Retrieval results from four different sources are presented: three are from scientific products (LATMOS, LISA, LPMAA) and the fourth one is the pre-operational product distributed by EUMETSAT (version 4.2). The different products are derived from different algorithms with different approaches. The difference and their implications for the retrieved products are discussed. In order to evaluate the quality and the performance of each product, comparisons with the vertical ozone concentration profiles measured by balloon sondes are performed and lead to estimates of the systematic and random errors in the IASI ozone products (profiles and partial columns). A first comparison is performed on the given profiles; a second comparison takes into account the altitude dependent sensitivity of the retrievals. Tropospheric columnar amounts are compared to the sonde for a lower tropospheric column (surface to about 6 km) and a total tropospheric column (surface to about 11 km). On average both tropospheric columns have small biases for the scientific products, less than 2 Dobson Units (DU) for the lower troposphere and less than 1 DU for the total troposphere. The comparison of the still pre-operational EUMETSAT columns shows higher mean differences of about 5 DU.
BibTeX:
@article{KeimEremenkoOrphalEtAl2009,
  author = {Keim, C. and Eremenko, M. and Orphal, J. and Dufour, G. and Flaud, J.-M. and Höpfner, M. and Boynard, A. and Clerbaux, C. and Payan, S. and Coheur, P.-F. and Hurtmans, D. and Claude, H. and Dier, H. and Johnson, B. and Kelder, H. and Kivi, R. and Koide, T. and Bartolomé, M.L. and Lambkin, K. and Moore, D. and Schmidlin, F.J. and Stübi, R.},
  title = {Tropospheric ozone from IASI: Comparison of different inversion algorithms and validation with ozone sondes in the northern middle latitudes},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {9329-9347},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-72849126581&doi=10.5194%2facp-9-9329-2009&partnerID=40&md5=d7415e6d2bf6dc1331ff7c9a6cbb6d41},
  doi = {10.5194/acp-9-9329-2009}
}
Abstract: Scientific findings from the last decades have clearly highlighted the need for a more comprehensive approach to atmospheric change processes. In fact, observation of atmospheric composition variables has been an important activity of atmospheric research that has developed instrumental tools (advanced analytical techniques) and platforms (instrumented passenger aircrafts, ground-based in situ and remote sensing stations, earth observation satellite instruments) providing essential information on the composition of the atmosphere. The variability of the atmospheric system and the extreme complexity of the atmospheric cycles for short-lived gaseous and aerosol species have led to the development of complex models to interpret observations, test our theoretical understanding of atmospheric chemistry and predict future atmospheric composition. The validation of numerical models requires accurate information concerning the variability of atmospheric composition for targeted species via comparison with observations and measurements. In this paper, we provide an overview of recent advances in instrumentation and methodologies for measuring atmospheric composition changes from space, aircraft and the surface as well as recent improvements in laboratory techniques that permitted scientific advance in the field of atmospheric chemistry. Emphasis is given to the most promising and innovative technologies that will become operational in the near future to improve knowledge of atmospheric composition. Our current observation capacity, however, is not satisfactory to understand and predict future atmospheric composition changes, in relation to predicted climate warming. Based on the limitation of the current European observing system, we address the major gaps in a second part of the paper to explain why further developments in current observation strategies are still needed to strengthen and optimise an observing system not only capable of responding to the requirements of atmospheric services but also to newly open scientific questions. © 2009 Elsevier Ltd. All rights reserved.
BibTeX:
@article{LajKlausenBildeEtAl2009,
  author = {Laj, P. and Klausen, J. and Bilde, M. and Plaß-Duelmer, C. and Pappalardo, G. and Clerbaux, C. and Baltensperger, U. and Hjorth, J. and Simpson, D. and Reimann, S. and Coheur, P.-F. and Richter, A. and De Mazière, M. and Rudich, Y. and McFiggans, G. and Torseth, K. and Wiedensohler, A. and Morin, S. and Schulz, M. and Allan, J.D. and Attié, J.-L. and Barnes, I. and Birmili, W. and Cammas, J.P. and Dommen, J. and Dorn, H.-P. and Fowler, D. and Fuzzi, S. and Glasius, M. and Granier, C. and Hermann, M. and Isaksen, I.S.A. and Kinne, S. and Koren, I. and Madonna, F. and Maione, M. and Massling, A. and Moehler, O. and Mona, L. and Monks, P.S. and Müller, D. and Müller, T. and Orphal, J. and Peuch, V.-H. and Stratmann, F. and Tanré, D. and Tyndall, G. and Abo Riziq, A. and Van Roozendael, M. and Villani, P. and Wehner, B. and Wex, H. and Zardini, A.A.},
  title = {Measuring atmospheric composition change},
  journal = {Atmospheric Environment},
  year = {2009},
  volume = {43},
  pages = {5351-5414},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70350060209&doi=10.1016%2fj.atmosenv.2009.08.020&partnerID=40&md5=af88984a68218efb87097d920efb93d6},
  doi = {10.1016/j.atmosenv.2009.08.020}
}
Abstract: With the use of data assimilation, we study the quality of the Infrared Atmospheric Sounding Interferometer (IASI) total ozone column measurements. The IASI data are provided by the inversion of IASI radiances performed at the Laboratoire ATmosphères, Milieux, Observations Spatiales (LATMOS). This data set is initially compared on a five-month period to a three-dimensional time varying ozone field that we take as a reference. This reference field results from the combined assimilation of ozone profiles from the Microwave Limb Sounder (MLS) instrument and of total ozone columns from the SCanning Imaging Absorption spectrometer for Atmospheric CHartographY (SCIAMACHY) instrument. It has low systematic and random errors when compared to ozonesondes and Ozone Monitoring Instrument (OMI) data. The comparison shows that on average, the LATMOS-IASI data tends to overestimate the total ozone columns by 2% to 8%. The random observation error of the LATMOS-IASI data is estimated to about 7%, except over polar regions and deserts where it is higher. The daytime data have generally lower biases but higher random error than the nighttime data. Using this information, the LATMOS-IASI data are then assimilated, combined with the MLS data. This first LATMOS-IASI data assimilation experiment shows that the resulting analysis is quite similar to the one obtained from the combined MLS and SCIAMACHY data assimilation. The differences are mainly due to the lack of SCIAMACHY measurements during polar night, and to the higher LATMOS-IASI random errors especially over the southern polar region. © 2009 Author(s).
BibTeX:
@article{MassartClerbauxCariolleEtAl2009,
  author = {Massart, S. and Clerbaux, C. and Cariolle, D. and Piacentini, A. and Turquety, S. and Hadji-Lazaro, J.},
  title = {First steps towards the assimilation of IASI ozone data into the MOCAGE-PALM system},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {5073-5091},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051998329&doi=10.5194%2facp-9-5073-2009&partnerID=40&md5=9e56fcdaf59a0363b3a4644cc556d68e},
  doi = {10.5194/acp-9-5073-2009}
}
Abstract: We present a line shape analysis of the P(2) and P(7) transitions of CO broadened by Xe in the fundamental band. The spectra were recorded at 349 K using a difference frequency laser spectrometer. To obtain information on the influence of Dicke narrowing, relaxation speed dependence, and line mixing effects, several models for implementation of Dicke narrowing and (or) speed-dependent effects are discussed. From experimental data analysis, we conclude that line shape models taking into account the Dicke effect only fail in the high pressure regime and lead to optical diffusion parameters that are much larger than the kinetic diffusion ones. On the contrary, a fair interpretation of data is obtained from speed-dependent models, so that it is possible to derive a quantitative estimate of optical diffusion effects that appear much smaller than the kinetic diffusion ones. Xe-broadening coefficients of CO lines in the fundamental band at 297 and 349 K are calculated from a semiclassical formalism involving successively two intermolecular potentials, the atom-atom Lennard-Jones model, and a three-term expansion of Legendre polynomials with four adjustable parameters.
BibTeX:
@article{Predoi-CrossRohartBouanichEtAl2009,
  author = {Predoi-Cross, A. and Rohart, F. and Bouanich, J.-P. and Hurtmans, D.R.},
  title = {Xenon-broadened CO line shapes in the fundamental band at 349 K},
  journal = {Canadian Journal of Physics},
  year = {2009},
  volume = {87},
  pages = {485-498},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68649129088&doi=10.1139%2fP08-123&partnerID=40&md5=c71b5b2677a7aa4cc305e6cfadfd092f},
  doi = {10.1139/P08-123}
}
Abstract: Although the global methane (CH4) concentration has more than doubled since pre-industrial times, local emission sources are still poorly identified and quantified. Instruments onboard satellites can improve our knowledge about the methane global distribution owing to their very good spatial coverage. The IASI (Infrared Atmospheric Sounding Interferometer) instrument launched on the European MetOp-A platform is a Fourier transform spectrometer which measures the thermal infrared radiation emitted by the Earth and its atmosphere. In this paper, we present the first global distribution of methane total columns (mostly sensitive to the middle troposphere) from the IASI spectra using the methane &amp;nu;4 absorption band. The retrieval spectral range was set in order to minimize possible spectroscopic issues. Results are discussed in terms of error budget and vertical sensitivity. In addition, we study the gain of information on surface methane concentrations provided by using the &amp;nu;3 band, which is partly covered by IASI on the short-wave end of the spectra (extending to 2760 cm&amp;minus;1), where solar reflection contributes significantly.
BibTeX:
@article{RazaviClerbauxWespesEtAl2009,
  author = {Razavi, A. and Clerbaux, C. and Wespes, C. and Clarisse, L. and Hurtmans, D. and Payan, S. and Camy-Peyret, C. and Coheur, P.F.},
  title = {Characterization of methane retrievals from the IASI space-borne sounder},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {7889-7899},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70549091124&doi=10.5194%2facp-9-7889-2009&partnerID=40&md5=7002d2e3a99bdf95f4b8424b1696ee13},
  doi = {10.5194/acp-9-7889-2009}
}
Abstract: Satellite-based remote sensing measurements of volcanic sulfur dioxide (SO2) provide critical information for reducing volcanic hazards. This paper describes the use of SO2 measurements from the thermal infrared sounder IASI and the UV-VIS instrument GOME-2 in services related to aviation hazard and early warning of volcanic unrest. The high sensitivity of both instruments to SO2 allows the detection and global tracking of volcanic eruption plumes and makes them a valuable tool for volcanic aviation hazard mitigation. The GOME-2 and IASI SO2 data are produced in near-real time and distributed to the Volcanic Ash Advisory Centers (VAACS) to assist them in issuing alerts to airlines and air traffic control organizations. Examples of recent eruptions affecting air traffic are presented including Jebel al Tair (Yemen, September 2007), Mount Okmok (Alaska, July 2008), and Mount Kasatochi (Alaska, August 2008). In addition, GOME-2 can detect changes in the SO2 emissions from passively degassing volcanoes and, therefore, provide critical information for hazard assessment. The monitoring of pre-emptive degassing by GOME-2 is used in early warning of volcanic activity by a mobile volcano fast response system in combination with numerous other parameters, such as seismicity, deformation, and thermal anomalies. © 2009, The Institute of Electrical and Electronics Engineers, Inc.
BibTeX:
@article{RixValksHaoEtAl2009,
  author = {Rix, M. and Valks, P. and Hao, N. and Loyola, D.G.R. and Zimmer, W. and Emmadi, S. and Rix, M. and van Geffen, J. and Clerbaux, C. and Clerbaux, C. and Clarisse, L. and Coheur, P.-F. and Erbertseder, T.},
  title = {Satellite Monitoring of Volcanic Sulfur Dioxide Emissions for Early Warning of Volcanic Hazards},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  year = {2009},
  volume = {2},
  pages = {196-206},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77951621408&doi=10.1109%2fJSTARS.2009.2031120&partnerID=40&md5=cdafad595fcb914079a06b7b2e8dd062},
  doi = {10.1109/JSTARS.2009.2031120}
}
Abstract: In this paper, we analyze the performance of the Infrared Atmospheric Sounding Interferometer (IASI), launched in October 2006 on board METOP-A, for the monitoring of carbon monoxide (CO) during extreme fire events, focusing on the record-breaking fires which devastated thousands of square kilometers of forest in Greece during the last week (23-30) of August 2007. After an assessment of the quality of the profiles retrieved using the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, the information provided on fire emissions and subsequent pollution outflow is discussed. Large CO plumes were observed above the Mediterranean Basin and North Africa, with total CO columns exceeding 24×1018 molecules/cm2 and absolute volume mixing ratios up to 4 ppmv on the 25 August. Up to 30×1018 molecules/cm2 and 22 ppmv in the lower troposphere are retrieved close to the fires above the Peloponnese, but with larger uncertainty. The average root-mean-square (RMS) difference between simulated and observed spectrais close to the estimated radiometric noise level, slightly increasing (by ∼14%) in the fresh fire plumes. CO profiles are retrieved with a vertical resolution of about 8 km, with ∼1.7 pieces of independent information on the vertical in the region considered and a maximum sensitivity in the free troposphere (∼4-5 km). Using the integrated total amount, the increase in CO burden due to these fires is estimated to 0.321 Tg, ∼40% of the total annual anthropogenic emissions in Greece. The patterns of these CO enhance- ments are in good agreement with the aerosol optical depth (AOD) retrieved from the MODIS measurements, highlighting a rapid transport of trace gases and aerosols across the Mediterranean Basin (less than one day). While the coarse vertical resolution will not allow the location of the exact plume height, the large CO enhancements observed in the lower troposphere are consistent with the maximum aerosol backscatter coefficient at ∼2 km detected by the CALIPSO lidar in space (CALIOP). © Author(s) 2009.
BibTeX:
@article{TurquetyHurtmansHadji-LazaroEtAl2009,
  author = {Turquety, S. and Hurtmans, D. and Hadji-Lazaro, J. and Coheur, P.-F. and Clerbaux, C. and Josset, D. and Tsamalis, C.},
  title = {Tracking the emission and transport of pollution from wildfires using the IASI CO retrievals: Analysis of the summer 2007 Greek fires},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {4897-4913},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70450246001&doi=10.5194%2facp-9-4897-2009&partnerID=40&md5=7388c84eaa21b0d88e7dcda6e0c8610b},
  doi = {10.5194/acp-9-4897-2009}
}
Abstract: This paper presents the first global distributions of HNO3 total columns acquired by the Infrared Atmospheric Sounding Interferometer (IASI) instrument, launched onboard the MetOp platform in October 2006. IASI is an infrared nadir-looking Fourier transform spectrometer providing atmospheric radiance spectra at 0.5 cm?1 spectral resolution, from which temperature and infrared absorbing gas concentration profiles are retrieved with global Earth coverage twice a day. A first analysis of the IASI measurements in terms of information content demonstrates the possibility of retrieving a total column for HNO3 at all latitudes with a maximal sensitivity in the middle stratosphere. The retrievals are performed from IASI spectra in the atmospheric window using a fast radiative transfer model and inversion software (FORLI) relying on the Optimal Estimation Method. The operational processing of HNO3 total columns is achieved since March 2008. We show that FORLI-HNO3 performs well at all latitudes (RMS of the spectral residuals around 2.3×10?6 W/m2 srm?1) and provides HNO3 total columns with on average statistical errors of about 12%, reaching the threshold value of 32% at the equatorial belt. The global distributions of the retrieved total columns for one year (from March 2008 to February 2009) are presented and discussed with emphasis given to seasonal and interhemispheric variations. Local seasonal variations at 6 specific locations are also described and discussed in comparison with MLS volume mixing ratios at 46.5 hPa. The seasonal cycle observedin Polar regions is highlighted, with maxima observed in fallwinter and minima during spring-summer. The denitrification inside the Antarctic polar vortex during winter is clearly revealed with unprecedented horizontal resolution: HNO 3 columns decreasing down to about 1×cm?2 are observed, which is consistent with the lower values of temperature observed between 50 and 15 hPa (∼20-25 km) and the resulting formation and sedimentation of polar stratospheric clouds. During the same period, the collar region of high quantities of HNO3 at the vortex edge is also observed around 65-60° S latitude. Preliminary correlations between IASI derived HNO3 and O3 columns inside the polar vortex are presented and discussed. © 2009 Author(s).
BibTeX:
@article{WespesHurtmansClerbauxEtAl2009,
  author = {Wespes, C. and Hurtmans, D. and Clerbaux, C. and Santee, M.L. and Martin, R.V. and Coheur, P.F.},
  title = {Global distributions of nitric acid from IASI/MetOP measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2009},
  volume = {9},
  pages = {7949-7962},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-71149107086&doi=10.5194%2facp-9-7949-2009&partnerID=40&md5=d842663b0b6d71a857acb3f256910c0b},
  doi = {10.5194/acp-9-7949-2009}
}
Abstract: In this paper we demonstrate the potential of the infrared Fourier transform spectrometer IASI in analysing volcanic eruptions, using the September 2007 eruption at Jebel at Tair as an illustrative example. Detailed radiative transfer calculations are presented, simulating IASI-like transmittance spectra for a variety of volcanic plumes. We analyse the sensitivity of IASI to SO 2 at different altitudes and demonstrate that IASI is in principle capable of sensing SO2 down to the surface. Using the brightness temperature difference of well chosen SO2 channels as a filter, we are able to track the plume of the Jebel at Tair eruption for 12 days, on a par with state of the art UV sounders. A method is presented for quickly estimating the altitude of a volcanic plume based on the relative intensities of the SO2 absorption lines. Despite recent advances, it is still very challenging to retrieve vertical profiles of SO2 from nadir viewing satellites. Currently the most accurate profiles in nadir are retrieved using backtracking of the plume with atmospheric transport models. Via full inverse retrievals using the optimal estimation method, we show the possibility of extracting medium coarse vertical profiles from IASI data. The retrieval allows us to present an evolution of the total mass of SO2 in the plume for the Jebel at Tair eruption. An analytical relation is derived between brightness temperature differences and concentrations, which fits the experimental data very well. The spectral range of IASI also allows retrieval of volcanic aerosols. In the initial plume of the Jebel at Tair eruption, volcanic aerosols were found in the form of ice particles, for which we derived particle sizes. © Author(s) 2008.
BibTeX:
@article{ClarisseCoheurPrataEtAl2008,
  author = {Clarisse, L. and Coheur, P.F. and Prata, A.J. and Hurtmans, D. and Razavi, A. and Phulpin, T. and Hadji-Lazaro, J. and Clerbaux, C.},
  title = {Tracking and quantifying volcanic SO2 with IASI, the September 2007 eruption at Jebel at Tair},
  journal = {Atmospheric Chemistry and Physics},
  year = {2008},
  volume = {8},
  pages = {7723-7734},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67651133559&doi=10.5194%2facp-8-7723-2008&partnerID=40&md5=9b617582feae38da4ede4dd4fb696d51},
  doi = {10.5194/acp-8-7723-2008}
}
Abstract: Satellite measurements are now recognized as a key element for the early detection and characterization of volcanic eruptions, in particular in the context of aircraft routing. A common tracer of volcanic plumes is sulfur dioxide (SO2), which so far has been measured by ultraviolet-visible (UV-vis) instruments and multispectral infrared (IR) sounders. Here we report the first SO2 vertical profile retrieved from high spectral resolution thermal infrared nadir radiance spectra and we provide information on both the quantity of gas emitted and its altitude. From the radiance spectra provided by the Tropospheric Emission Spectrometer (TES) aboard the NASA AURA satellite, and owing to the ∼0.1 cm-1 (apodized) spectral resolution, elevated levels of SO2 were measured following volcanic eruptions occurring in 2005 (Manam, Sierra Negra) and 2006 (Rabaul, Nyamuragira). Column values are found to be in good agreement with the data provided by Ozone Mapping Instrument (OMI), a UV-vis instrument also onboard the AURA satellite. Copyright 2008 by the American Geophysical Union.
BibTeX:
@article{ClerbauxCoheurClarisseEtAl2008,
  author = {Clerbaux, C. and Coheur, P.-F. and Clarisse, L. and Hadji-Lazaro, J. and Hurtmans, D. and Turquety, S. and Bowman, K. and Worden, H. and Carn, S.A.},
  title = {Measurements of so2 profiles in volcanic plumes from the NASA Tropospheric Emission Spectrometer (TES)},
  journal = {Geophysical Research Letters},
  year = {2008},
  volume = {35},
  article number = {L22807},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-60149089844&doi=10.1029%2f2008GL035566&partnerID=40&md5=6611aed2259d9fe6c8f0e885439d1cfc},
  doi = {10.1029/2008GL035566}
}
Abstract: Carbon monoxide (CO) is a key species for tracking pollution plumes. The Measurement Of Pollution in The Troposphere (MOPITT) mission onboard the Terra satellite has already provided 7.5 years of CO atmospheric concentration measurements around the globe. Limited sensitivity to the boundary layer is well known to be a weakness of nadir looking thermal infrared sounders. This paper investigates the possibility of using the MOPITT surface measurements to detect CO emitted by cities and urban centers. By selecting the data and averaging them over long time periods, we demonstrate that the CO pollution arising from the large cities and urban areas can be distinguished from the background transported pollution. The more favorable observations are obtained during daytime and at locations where the thermal contrast (temperature gradient) between the surface and lower atmosphere is significant. Copyright 2008 by the American Geophysical Union.
BibTeX:
@article{ClerbauxEdwardsDeeterEtAl2008,
  author = {Clerbaux, C. and Edwards, D.P. and Deeter, M. and Emmons, L. and Lamarque, J.-F. and Tie, X.X. and Massie, S.T. and Gille, J.},
  title = {Carbon monoxide pollution from cities and urban areas observed by the Terra/MOPITT mission},
  journal = {Geophysical Research Letters},
  year = {2008},
  volume = {35},
  article number = {L03817},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-41849084484&doi=10.1029%2f2007GL032300&partnerID=40&md5=fa8fbf231daa2efd78d6d2003e23fe80},
  doi = {10.1029/2007GL032300}
}
Abstract: The Atmospheric Chemistry Experiment (ACE) mission was launched in August 2003 to sound the atmosphere by solar occultation. Carbon monoxide (CO), a good tracer of pollution plumes and atmospheric dynamics, is one of the key species provided by the primary instrument, the ACE-Fourier Transform Spectrometer (ACE-FTS). This instrument performs measurements in both the CO 1-0 and 2-0 ro-vibrational bands, from which vertically resolved CO concentration profiles are retrieved, from the mid-troposphere to the thermosphere. This paper presents an updated description of the ACE-FTS version 2.2 CO data product, along with a comprehensive validation of these profiles using available observations (February 2004 to December 2006). We have compared the CO partial columns with ground-based measurements using Fourier transform infrared spectroscopy and millimeter wave radiometry, and the volume mixing ratio profiles with airborne (both high-altitude balloon flight and airplane) observations. CO satellite observations provided by nadir-looking instruments (MOPITT and TES) as well as limb-viewing remote sensors (MIPAS, SMR and MLS) were also compared with the ACE-FTS CO products. We show that the ACE-FTS measurements provide CO profiles with small retrieval errors (better than 5% from the upper troposphere to 40 km, and better than 10% above). These observations agree well with the correlative measurements, considering the rather loose coincidence criteria in some cases. Based on the validation exercise we assess the following uncertainties to the ACE-FTS measurement data: better than 15% in the upper troposphere (8-12 km), than 30% in the lower stratosphere (12-30 km), and than 25% from 30 to 100 km. © Author(s) 2008.
BibTeX:
@article{ClerbauxGeorgeTurquetyEtAl2008,
  author = {Clerbaux, C. and George, M. and Turquety, S. and Walker, K.A. and Barret, B. and Bernath, P. and Boone, C. and Borsdorff, T. and Cammas, J.P. and Catoire, V. and Coffey, M. and Coheur, P.-F. and Deeter, M. and De Mazière, M. and Drummond, J. and Duchatelet, P. and Dupuy, E. and De Zafra, R. and Eddounia, F. and Edwards, D.P. and Emmons, L. and Funke, B. and Gille, J. and Griffith, D.W.T. and Hannigan, J. and Hase, F. and Höpfner, M. and Jones, N. and Kagawa, A. and Kasai, Y. and Kramer, I. and Le Flochmoën, E. and Livesey, N.J. and López-Puertas, M. and Luo, M. and Mahieu, E. and Murtagh, D. and Nédélec, P. and Pazmino, A. and Pumphrey, H. and Ricaud, P. and Rinsland, C.P. and Robert, C. and Schneider, M. and Senten, C. and Stiller, G. and Strandberg, A. and Strong, K. and Sussmann, R. and Thouret, V. and Urban, J. and Wiacek, A.},
  title = {CO measurements from the ACE-FTS satellite instrument: Data analysis and validation using ground-based, airborne and spaceborne observations},
  journal = {Atmospheric Chemistry and Physics},
  year = {2008},
  volume = {8},
  pages = {2569-2594},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-47149092921&doi=10.5194%2facp-8-2569-2008&partnerID=40&md5=9f7375e9282ed368bfd35b38f98372ba},
  doi = {10.5194/acp-8-2569-2008}
}
Abstract: The development of Gestion et Etude des Informations Spectroscopiques Atmosphériques (GEISA: Management and Study of Spectroscopic Information) was started over three decades at Laboratoire de Météorologie Dynamique (LMD) in France. GEISA is a computer accessible spectroscopic database, designed to facilitate accurate forward radiative transfer calculations using a line-by-line and layer-by-layer approach. More than 350 users have been registered for on-line use of the GEISA facilities. The current 2003 edition of GEISA (GEISA-03) is a system comprising three independent sub-databases devoted respectively to: line transition parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols. Currently, GEISA is involved in activities related to the assessment of the capabilities of IASI (Infrared Atmospheric Sounding Interferometer on board of the METOP European satellite) through the GEISA/IASI database derived from GEISA. The GEISA-03 content is presented, placing emphasis on molecular species of interest for Earth and planetary atmosphere studies, with details on the updated 2008 archive underway. A critical assessment on the needs, in terms of molecular parameters archive, related with recent satellite astrophysical missions is made. Detailed information on free on-line GEISA and GEISA/IASI access is given at http://ara.lmd.polytechnique.fr and http://ether.ipsl.jussieu.fr. © 2008 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Jacquinet-HussonScottChedinEtAl2008,
  author = {Jacquinet-Husson, N. and Scott, N.A. and Chédin, A. and Crépeau, L. and Armante, R. and Capelle, V. and Orphal, J. and Coustenis, A. and Boonne, C. and Poulet-Crovisier, N. and Barbe, A. and Birk, M. and Brown, L.R. and Camy-Peyret, C. and Claveau, C. and Chance, K. and Christidis, N. and Clerbaux, C. and Coheur, P.F. and Dana, V. and Daumont, L. and De Backer-Barilly, M.R. and Di Lonardo, G. and Flaud, J.M. and Goldman, A. and Hamdouni, A. and Hess, M. and Hurley, M.D. and Jacquemart, D. and Kleiner, I. and Köpke, P. and Mandin, J.Y. and Massie, S. and Mikhailenko, S. and Nemtchinov, V. and Nikitin, A. and Newnham, D. and Perrin, A. and Perevalov, V.I. and Pinnock, S. and Régalia-Jarlot, L. and Rinsland, C.P. and Rublev, A. and Schreier, F. and Schult, L. and Smith, K.M. and Tashkun, S.A. and Teffo, J.L. and Toth, R.A. and Tyuterev, Vl.G. and Vander Auwera, J. and Varanasi, P. and Wagner, G.},
  title = {The GEISA spectroscopic database: Current and future archive for Earth and planetary atmosphere studies},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2008},
  volume = {109},
  pages = {1043-1059},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-40849102711&doi=10.1016%2fj.jqsrt.2007.12.015&partnerID=40&md5=fa711f9786db2ebbb6a1bbcdd2982419},
  doi = {10.1016/j.jqsrt.2007.12.015}
}
Abstract: Identification of phytoplankton groups from space is essential to map and monitor algal blooms in coastal waters, but remains a challenge due to the presence of suspended sediments and dissolved organic matter which interfere with phytoplankton signal. On the basis of field measurements of remote sensing reflectance (Rrs(λ)), bio-optical parameters, and phytoplankton cells enumerations, we assess the feasibility of using multispectral and hyperspectral approaches for detecting spring blooms of Phaeocystis globosa (P. globosa). The two reflectance ratios (Rrs(490) /Rrs(510) and Rrs(442.5) /Rrs(490)), used in the multispectral inversion, suggest that detection of P. globosa blooms are possible from current ocean color sensors. The effects of chlorophyll concentration, colored dissolved organic matter (CDOM), and particulate matter composition on the performance of this multispectral approach are investigated via sensitivity analysis. This analysis indicates that the development of a remote sensing algorithm, based on the values of these two ratios, should include information about CDOM concentration. The hyperspectral inversion is based on the analysis of the second derivative of Rrs(λ) (dλ2 Rrs). Two criteria, based on the position of the maxima and minima of dλ2Rrs, are established to discriminate the P. globosa blooms from diatoms blooms. We show that the position of these extremes is related to the specific absorption spectrum of P. globosa and is significantly correlated with the relative biomass of P. globosa. This result confirms the advantage of a hyperspectral over multispectral inversion for species identification and enumeration from satellite observations of ocean color. Copyright 2008 by the American Geophysical Union.
BibTeX:
@article{LubacLoiselGuiselinEtAl2008,
  author = {Lubac, B. and Loisel, H. and Guiselin, N. and Astoreca, R. and Artigas, L.F. and Mériaux, X.},
  title = {Hyperspectral and multispectral ocean color inversions to detect Phaeocystis globosa blooms in coastal waters},
  journal = {Journal of Geophysical Research: Oceans},
  year = {2008},
  volume = {113},
  article number = {C06026},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-51449110184&doi=10.1029%2f2007JC004451&partnerID=40&md5=5c6cea983bcbbe01d407b932b7a203c2},
  doi = {10.1029/2007JC004451}
}
Abstract: This paper reports accurate line positions, intensities, self-broadening, -shift and -line mixing coefficients for 56 rotational transitions from multispectrum fits of low noise, high-resolution Fourier-transform spectra. The measured line intensities are within the statistical spread of the previous measurements available in the literature-thus contributing to the efforts to measure the oxygen A-band intensities with an accuracy better than 1%. We determined the integrated band strength and Einstein A coefficient. Using our spectrum calibration method we could clearly show for the first time that there is a meaningful statistical discrepancy in the frequency standards used in spectroscopic studies for the oxygen A-band. We were able to explain how this discrepancy leads to two different sets of shifts reported in the literature and demonstrate the need for precise frequency-type transition wavenumber measurements of the oxygen A-band transitions. We observed deviations from the conventional Voigt profile due to speed-dependent broadening and line mixing effects. Dicke narrowing was observed on a selected group of spectra recorded at pressures between 98 and 337 Torr. The Dicke narrowed lineshapes were best modeled using a Galatry profile implemented using a fixed value for the velocity-changing collision rate. The weak line mixing coefficients were determined from fits using the speed-dependent models. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws were used to calculate the self-broadening and self-line mixing coefficients. © 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{Predoi-CrossHambrookKellerEtAl2008,
  author = {Predoi-Cross, A. and Hambrook, K. and Keller, R. and Povey, C. and Schofield, I. and Hurtmans, D. and Over, H. and Mellau, G.Ch.},
  title = {Spectroscopic lineshape study of the self-perturbed oxygen A-band},
  journal = {Journal of Molecular Spectroscopy},
  year = {2008},
  volume = {248},
  pages = {85-110},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-40249110033&doi=10.1016%2fj.jms.2007.11.007&partnerID=40&md5=cf642ddabcf40749b2894d0ec81a03d0},
  doi = {10.1016/j.jms.2007.11.007}
}
Abstract: We report measurements for N2-broadening, pressure-shift and line mixing coefficients for 55 oxygen transitions in the A-band retrieved using a multispectrum fitting technique. Nineteen laboratory absorption spectra were recorded at 0.02 cm-1 resolution using a multi-pass absorption cell with path length of 1636.9 cm and the IFS 120 Fourier transform spectrometer located at Justus-Liebig-University in Giessen, Germany. The total sample pressures ranged from 8.8 to 3004.5 Torr with oxygen volume mixing ratios in nitrogen ranging between 0.057 and 0.62. An Exponential Power Gap (EPG) scaling law was used to calculate the N2-broadening and N2-line mixing coefficients. The line broadening and shift coefficients for the A-band of oxygen self-perturbed and perturbed by N2 are modeled using semiclassical calculations based on the Robert-Bonamy formalism and two intermolecular potentials. These potentials involve electrostatic contributions including the hexadecapole moment of the molecules and (a) a simple dispersion contribution with one adjustable parameter to fit the broadening coefficients or (b) the atom-atom Lennard-Jones model without such adjustable parameters. The first potential leads to very weak broadening coefficients for high J transitions whereas the second potential gives much more improved results at medium and large J values, in reasonable agreement with the experimental data. For the line shifts which mainly arise in our calculation from the electronic state dependence of the isotropic potential, their general trends with increasing J values can be well predicted, especially from the first potential. From the theoretical results, we have derived air-broadening and air-induced shift coefficients with an agreement comparable to that obtained for O2-O2 and O2-N2. © 2008 Elsevier Inc. All rights reserved.
BibTeX:
@article{Predoi-CrossHolladayHeungEtAl2008,
  author = {Predoi-Cross, A. and Holladay, C. and Heung, H. and Bouanich, J.-P. and Mellau, G.Ch. and Keller, R. and Hurtmans, D.R.},
  title = {Nitrogen-broadened lineshapes in the oxygen A-band: Experimental results and theoretical calculations},
  journal = {Journal of Molecular Spectroscopy},
  year = {2008},
  volume = {251},
  pages = {159-175},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-50149120532&doi=10.1016%2fj.jms.2008.02.010&partnerID=40&md5=725dde096cf2fbacf92e0357f59ad563},
  doi = {10.1016/j.jms.2008.02.010}
}
Abstract: This work is a room temperature study of the 30012 ← 00001 and 30013 ← 00001 vibrational bands in self- and air-broadened carbon dioxide. The spectra were recorded at a resolution of 0.008 cm-1 or 0.009 cm -1 using a Fourier transform spectrometer and a temperature stabilized long path absorption cell. The analysis is performed using a multispectrum nonlinear least squares fitting technique where the spectra are fitted simultaneously in spectral intervals of about 3 cm-1. Voigt and Speed Dependent Voigt line shape models are used. Intensities, self- and air-broadening, shifts, and weak line mixing coefficients are determined and compared with other studies. Comparisons are also made to demonstrate the importance of considering the line shape effects for measurements in Earth's atmosphere using satellite remote sensing. Examples of multispectrum fits with and without the inclusion of line mixing are also given. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws are used to calculate the relaxation matrix elements and model the broadening and line mixing coefficients. © 2008 American Institute of Physics.
BibTeX:
@conference{Predoi-CrossMcKellarHurtmans2008,
  author = {Predoi-Cross, A. and McKellar, A.R.W. and Hurtmans, D.R.},
  title = {High accuracy line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide},
  journal = {AIP Conference Proceedings},
  year = {2008},
  volume = {1058},
  pages = {265-272},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-57049137884&doi=10.1063%2f1.3026459&partnerID=40&md5=aaf261d09b15b01f6a229d6847228c23},
  doi = {10.1063/1.3026459}
}
Abstract: We present a line shape analysis on the P(2) and P(7) transitions of CO broadened by Xe in the fundamental band. The spectra were recorded at 349 K using a difference frequency laser spectrometer. For line shape analysis, line mixing effects were included and several models describing the Dicke effect were considered. It is shown that retrieved diffusion parameters are pressure dependent and larger than kinetic diffusion parameters. Finally, all these Dicke line shape models fail in the high pressure regime, that rules out the appropriateness of the Dicke effect for the CO-Xe system. © 2008 American Institute of Physics.
BibTeX:
@conference{Predoi-CrossRohartBouanichEtAl2008,
  author = {Predoi-Cross, A. and Rohart, F. and Bouanich, J.-P. and Hurtmans, D.R.},
  title = {Xe-broadened CO line shapes in the fundamental band at 349 K},
  journal = {AIP Conference Proceedings},
  year = {2008},
  volume = {1058},
  pages = {178-180},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-57049097743&doi=10.1063%2f1.3026438&partnerID=40&md5=ce0e93f829255c0977576557e3880bd1},
  doi = {10.1063/1.3026438}
}
BibTeX:
@article{Predoi-CrossUnniLiuEtAl2008,
  author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.},
  title = {Corrigendum to "Line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide perturbed by air" [J. Mol. Spectrosc. 246 (2007) 98-112] (DOI:10.1016/j.jms.2007.08.008)},
  journal = {Journal of Molecular Spectroscopy},
  year = {2008},
  volume = {249},
  pages = {121},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-43849112801&doi=10.1016%2fj.jms.2008.03.001&partnerID=40&md5=3f3b0189be985d415bf734c1883c605f},
  doi = {10.1016/j.jms.2008.03.001}
}
BibTeX:
@article{Predoi-CrossUnniLiuEtAl2008a,
  author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.},
  title = {Corrigendum to "Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing and speed dependence" [J. Mol. Spectrosc. 245 (2007) 34-51] (DOI:10.1016/j.jms.2007.07.004)},
  journal = {Journal of Molecular Spectroscopy},
  year = {2008},
  volume = {249},
  pages = {72},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-42149116841&doi=10.1016%2fj.jms.2008.02.011&partnerID=40&md5=bef2059e0e9bfedd472f7dd4896d4f83},
  doi = {10.1016/j.jms.2008.02.011}
}
Abstract: High spectral resolution Fourier transform spectrometer (FTS) measurements of tropospheric carbon monoxide (CO) distributions show mixing ratios over Indonesia during October 2006 of ∼200 ppbv (10-9 per unit volume) in the middle troposphere. The elevated emissions were caused by intense and widespread Indonesian peat and forest fire emissions elevated compared to other years by the impact of a moderate El Niño/Soutern Oscillation (ENSO) event, which delayed that year's monsoon season and produced very dry conditions. Moderate resolution imaging spectrometer (MODIS) fire counts, atmospheric chemistry experiment (ACE) measurements of elevated mixing ratios of fire emission products and near infrared extinction, and back trajectory calculations for a sample measurement location near the time of maximum emissions provide additional evidence that the elevated 2006 emissions resulted primarily from the Indonesia fires. Lower CO mixing ratios measured by ACE and fewer MODIS fire counts in Indonesia during October 2005 indicate lower emissions than during 2006. Coincident profiles from the ACE agree within the uncertainties with those from the tropospheric emission spectrometer (TES) for pressure ranges and time periods with good TES sensitivity after accounting for its lower vertical sensitivity compared with the ACE FTS. © 2007 Elsevier Ltd. All rights reserved.
BibTeX:
@article{RinslandLuoShephardEtAl2008,
  author = {Rinsland, C.P. and Luo, M. and Shephard, M.W. and Clerbaux, C. and Boone, C.D. and Bernath, P.F. and Chiou, L. and Coheur, P.F.},
  title = {Tropospheric emission spectrometer (TES) and atmospheric chemistry experiment (ACE) measurements of tropospheric chemistry in tropical southeast Asia during a moderate El Niño in 2006},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2008},
  volume = {109},
  pages = {1931-1942},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-43449115695&doi=10.1016%2fj.jqsrt.2007.12.020&partnerID=40&md5=401be7b3bccf8be1215487664c0df0e3},
  doi = {10.1016/j.jqsrt.2007.12.020}
}
Abstract: Following validation activities and corresponding improvements in processing algorithms over the first few years of the MERIS mission, the algal1 and algal2 products are now considered as sufficiently mature for use in applications in Belgian waters. The utility of this product has been enhanced by the development of a number of multitemporal products including single point time series, multitemporal composites (monthly/3-monthly means) and annual products such as the mean and 90 percentile concentrations and the timing of the spring bloom. Marine management applications include: support for the assessment of eutrophication status in the context of the Oslo and Paris Convention for the Prevention of Marine Pollution (OSPAR), optimisation of seaborne monitoring, detection of harmful algal blooms and support for aquaculture. More generally, the MERIS data is used in support of marine science including the validation of ecosystem models and may be used in the future for the estimation of air-sea carbon fluxes. The current status of these applications is described together with an assessment of the remaining scientific challenges as well as the future possibilities.
BibTeX:
@conference{RuddickParkAstorecaEtAl2008,
  author = {Ruddick, K. and Park, Y. and Astoreca, R. and Borges, A. and Lacroix, G. and Lancelot, C. and Rousseau, V.},
  title = {Applications of the MERIS algal pigment products in Belgian waters},
  journal = {European Space Agency, (Special Publication) ESA SP},
  year = {2008},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954565137&partnerID=40&md5=566fdaeb31f48d69686a0cad42060599}
}
Abstract: This paper describes the validation of MERIS water products for the Southern North Sea for the period July 2002 to September 2008. During this period, 39 matchups were obtained for the parameters water-leaving reflectance spectra, chlorophyll a concentration and total suspended matter concentration, of which 12 are in optimal conditions. Previous validation results reported for 2002-5 are updated to 2008. Conclusions are largely reinforced since the MERIS processor has not changed. In particular it is recommended to improve estimation of the spectral slope of aerosol reflectance in turbid waters. Some image artifacts are noted including noisy low chlorophyll data. Inherent optical property data is analysed and compared to the assumptions used for derivation of the MERIS products. Turbidity has been added to the in situ parameter set, strengthening quality control of water sample analysis.
BibTeX:
@conference{RuddickParkAstorecaEtAl2008a,
  author = {Ruddick, K. and Park, Y. and Astoreca, R. and Neukermans, G. and Van Mol, B.},
  title = {Validation of MERIS water products in the southern North Sea: 2002-2008},
  journal = {European Space Agency, (Special Publication) ESA SP},
  year = {2008},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954564040&partnerID=40&md5=3f2f75ce8753e22fe8eda8c84e026e01}
}
Abstract: Ground-based high spectral resolution Fourier-transform infrared (FTIR) solar absorption spectroscopy is a powerful remote sensing technique to obtain information on the total column abundances and on the vertical distribution of various constituents in the atmosphere. This work presents results from two FTIR measurement campaigns in 2002 and 2004, held at Ile de La Réunion (21° S, 55° E). These campaigns represent the first FTIR observations carried out at a southern (sub)tropical site. They serve the initiation of regular, long-term FTIR monitoring at this site in the near future. To demonstrate the capabilities of the FTIR measurements at this location for tropospheric and stratospheric monitoring, a detailed report is given on the retrieval strategy, information content and corresponding full error budget evaluation for ozone (O3), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), ethane (C 2H6), hydrogen chloride (HCl), hydrogen fluoride (HF) and nitric acid (HNO3) total and partial column retrievals. Moreover, we have made a thorough comparison of the capabilities at sea level altitude (St.-Denis) and at 2200 m a.s.l. (Maïdo). It is proved that the performances of the technique are such that the atmospheric variability can be observed, at both locations and in distinct altitude layers. Comparisons with literature and with correlative data from ozone sonde and satellite (i.e., ACE-FTS, HALOE and MOPITT) measurements are given to confirm the results. Despite the short time series available at present, we have been able to detect the seasonal variation of CO in the biomass burning season, as well as the impact of particular biomass burning events in Africa and Madagascar on the atmospheric composition above Ile de La Réunion. We also show that differential measurements between St.-Denis and Maïdo provide useful information about the concentrations in the boundary layer.
BibTeX:
@article{SentenDeMaziereDilsEtAl2008,
  author = {Senten, C. and De Mazière, M. and Dils, B. and Hermans, C. and Kruglanski, M. and Neefs, E. and Scolas, F. and Vandaele, A.C. and Vanhaelewyn, G. and Vigouroux, C. and Carleer, M. and Coheur, P.F. and Fally, S. and Barret, B. and Baray, J.L. and Delmas, R. and Leveau, J. and Metzger, J.M. and Mahieu, E. and Boone, C. and Walker, K.A. and Bernath, P.F. and Strong, K.},
  title = {Technical note: New ground-based FTIR measurements at Ile de la Réunion: Observations, error analysis, and comparisons with independent data},
  journal = {Atmospheric Chemistry and Physics},
  year = {2008},
  volume = {8},
  pages = {3483-3508},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-46749104519&doi=10.5194%2facp-8-3483-2008&partnerID=40&md5=7f5253483d17915d0b425328680bfd63},
  doi = {10.5194/acp-8-3483-2008}
}
Abstract: The results of nitrogen broadening measurements in the ν3 band of 12CH4 using the 5.37 m long absorption path length all-copper Herriott cell were presented. The experimental pressure shift data for 90 and for 140 K temperatures were plotted, where the pressure shift for each component was plotted versus pressure expressed in units of atmospheres. The comparison of values with the values given by HITRAN04 at 296 K show differences of -2.77×10-3cm-1atm-1 in absolute value compared to the database which is largely in the error bar. Absolute differences from 1.9 to 15.3×10-4cm-1atm-1 are observed for the room temperature pressure shift coefficient.
BibTeX:
@article{TumuhimbiseHurtmansMondelainEtAl2008,
  author = {Tumuhimbise, A.T. and Hurtmans, D. and Mondelain, D. and Mantz, A.W.},
  title = {Nitrogen-pressure shifts in the ν3 band of methane measured at several temperatures between 300 and 90 K},
  journal = {Journal of Molecular Spectroscopy},
  year = {2008},
  volume = {252},
  pages = {239-241},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-56349119270&doi=10.1016%2fj.jms.2008.09.001&partnerID=40&md5=d4e9458025dd34b3bb9d730bcde6a794},
  doi = {10.1016/j.jms.2008.09.001}
}
Abstract: This study presents the complementary picture of the pollution outflow provided by several satellite observations of carbon monoxide (CO), based on different observation techniques. This is illustrated by an analysis of the Asian outflow during the spring of 2005, through comparisons with simulations by the LMDz-INCA global chemistry transport model. The CO observations from the MOPITT and SCIAMACHY nadir sounders, which provide vertically integrated information with excellent horizontal sampling, and from the ACE-FTS solar occultation instrument, which has limited spatial coverage but allows the retrieval of vertical profiles, are used. Combining observations from MOPITT (mainly sensitive to the free troposphere) and SCIAMACHY (sensitive to the full column) allows a qualitative evaluation of the boundary layer CO. The model tends to underestimate this residual compared to the observations, suggesting underestimated emissions, especially in eastern Asia. However, a better understanding of the consistency and possible biases between the MOPITT and SCIAMACHY CO is necessary for a quantitative evaluation. Underestimated emissions, and possibly too low lofting and underestimated chemical production in the model, lead to an underestimate of the export to the free troposphere, as highlighted by comparisons with MOPITT and ACE-FTS. Both instruments observe large trans-Pacific transport extending from ∼20° N to ∼60° N, with high upper tropospheric CO observed by ACE-FTS above the eastern Pacific (with values of up to 300 ppbv around 50° N at 500 hPa and up to ∼200 ppbv around 30° N at 300 hPa). The low vertical and horizontal resolutions of the global model do not allow the simulation of the strong enhancements in the observed plumes. However, the transport patterns are well captured, and are mainly attributed to export from eastern Asia, with increasing contributions from South Asia and Indonesia towards the tropics. Additional measurements of C2H2, C2H 6 and HCN by ACE-FTS provide further information on the plume history. C2H2 and C2H6 enhancements are well correlated with the CO plumes, indicating common sources and rapid trans-Pacific transport. HCN observations show that the biomass burning contributes mainly at latitudes lower than ∼40° N. This study provides a first step towards a full combination of complementary observations, but also highlights the need for a better evaluation of consistency between the datasets in order to allow precise quantitative analyses.
BibTeX:
@article{TurquetyClerbauxLawEtAl2008,
  author = {Turquety, S. and Clerbaux, C. and Law, K. and Coheur, P.-F. and Cozic, A. and Szopa, S. and Hauglustaine, D.A. and Hadji-Lazaro, J. and Gloudemans, A.M.S. and Schrijver, H. and Boone, C.D. and Bernath, P.F. and Edwards, D.P.},
  title = {CO emission and export from Asia: An analysis combining complementary satellite measurements (MOPITT, SCIAMACHY and ACE-FTS) with global modeling},
  journal = {Atmospheric Chemistry and Physics},
  year = {2008},
  volume = {8},
  pages = {5187-5204},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-51049109429&doi=10.5194%2facp-8-5187-2008&partnerID=40&md5=2002df8475104d806f8bfc32baca4c9f},
  doi = {10.5194/acp-8-5187-2008}
}
Abstract: The high resolution laboratory spectrum of hot water vapour has been recorded in the 500-13 000 cm-1 wavenumber range and we report on the analysis of the 4750-13 000 cm-1 (0.769-2.1 μm) portion. The emission spectrum was recorded using an oxy-acetylene welding torch and a Fourier transform spectrometer. Line assignments in the laboratory spectrum as well as in an absorption spectrum of a sunspot umbra were made with the help of the BT2 line-list. Our torch spectrum is the first laboratory observation of the 9300 Å 'steam bands' seen in M-stars and brown dwarfs. © 2008 The Authors.
BibTeX:
@article{ZobovShirinOvsyannikovEtAl2008,
  author = {Zobov, N.F. and Shirin, S.V. and Ovsyannikov, R.I. and Polyansky, O.L. and Barber, R.J. and Tennyson, J. and Bernath, P.F. and Carleer, M. and Colin, R. and Coheur, P.-F.},
  title = {Spectrum of hot water in the 4750-13 000 cm-1 wavenumber range (0.769-2.1 μm)},
  journal = {Monthly Notices of the Royal Astronomical Society},
  year = {2008},
  volume = {387},
  pages = {1093-1098},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-45249112546&doi=10.1111%2fj.1365-2966.2008.13234.x&partnerID=40&md5=d9b8fba01443aa415edca5aad7540ab3},
  doi = {10.1111/j.1365-2966.2008.13234.x}
}
Abstract: We define the disentangling power of a unitary operator in a similar way as the entangling power defined by Zanardi et al. [P. Zanardi, C. Zalka, L. Faoro, Phys. Rev. A 62 (2000) 030301(R), quant-ph/0005031]. A general formula is derived and it is shown that both quantities are directly proportional. All results concerning the entangling power can simply be translated into similar statements for the disentangling power. In particular, the disentangling power is maximal for certain permutations derived from orthogonal Latin squares. These permutations can therefore be interpreted as those that distort entanglement in a maximal way. © 2007 Elsevier B.V. All rights reserved.
BibTeX:
@article{ClarisseGhoshSeveriniEtAl2007,
  author = {Clarisse, L. and Ghosh, S. and Severini, S. and Sudbery, A.},
  title = {The disentangling power of unitaries},
  journal = {Physics Letters, Section A: General, Atomic and Solid State Physics},
  year = {2007},
  volume = {365},
  pages = {400-402},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247484988&doi=10.1016%2fj.physleta.2007.02.001&partnerID=40&md5=4a85e60be4fe44641a89497c9429e307},
  doi = {10.1016/j.physleta.2007.02.001}
}
BibTeX:
@article{ClerbauxHadji-LazaroTurquetyEtAl2007,
  author = {Clerbaux, C. and Hadji-Lazaro, J. and Turquety, S. and George, M. and Coheur, P.-F. and Hurtmans, D. and Wespes, C. and Herbin, H. and Blumstein, D. and Tourniers, B. and Phulpin, T.},
  title = {The IASI/MetOp1Mission: First observations and highlights of its potential contribution to GMES2},
  journal = {Space Research Today},
  year = {2007},
  volume = {168},
  pages = {19-24},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547470284&doi=10.1016%2fS0045-8732%2807%2980046-5&partnerID=40&md5=839c4e1d27bdece7ff8d4452f7aa1dd0},
  doi = {10.1016/S0045-8732(07)80046-5}
}
Abstract: In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACEFTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they suggest that the emissions for this event likely originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE-FTS spectra over a wide wavenumber range (750-4400 cm-1), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) and CH3COO2NO2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.
BibTeX:
@article{CoheurHerbinClerbauxEtAl2007,
  author = {Coheur, P.-F. and Herbin, H. and Clerbaux, C. and Hurtmans, D. and Wespes, C. and Carleer, M. and Turquety, S. and Rinsland, C.P. and Remedios, J. and Hauglustaine, D. and Boone, C.D. and Bernath, P.F.},
  title = {ACE-FTS observation of a young biomass burning plume: First reported measurements of C2H4, C3H6O, H 2CO and PAN by infrared occultation from space},
  journal = {Atmospheric Chemistry and Physics},
  year = {2007},
  volume = {7},
  pages = {5437-5446},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35349029872&doi=10.5194%2facp-7-5437-2007&partnerID=40&md5=ada9198874f77c2b8aa130c08cf8372f},
  doi = {10.5194/acp-7-5437-2007}
}
Abstract: The isotopologic composition of water vapour in the atmosphere provides valuable information on many climate, chemical and dynamical processes. The accurate measurements of the water isotopologues by remote-sensing techniques remains a challenge, due to the large spatial and temporal variations. Simultaneous profile retrievals of the main water isotopologues (i.e. H 216O, H218O and HDO) and their ratios are presented here for the first time, along their retrieved global distributions. The results are obtained by exploiting the high resolution infrared spectra recorded by the Interferometric Monitor for Greenhouse gases (IMG) instrument, which has operated in the nadir geometry onboard the ADEOS satellite between 1996 and 1997. The retrievals are performed on cloud-free radiances, measured during ten days of April 1997, considering two atmospheric windows (1205-1228 cm-1; 2004-2032 cm-1) and using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM). Characterizations in terms of vertical sensitivity and error budget are provided. We show that a relatively high vertical resolution is achieved for H216O (∼4-5 km), and that the retrieved profiles are in fair agreement with local sonde measurements, at different latitudes. The retrieved global distributions of H216O, H218O, HDO and their ratios are presented and found to be consistent with previous experimental studies and models. The Ocean-Continent difference, the latitudinal and vertical dependence of the water vapour amount and the isotopologic depletion are notably well reproduced. Others trends, possibly related to small-scale variations in the vertical profiles are also discussed. Despite the difficulties encountered for computing accurately the isotopologic ratios, our results demonstrate the ability of infrared nadir sounding for monitoring atmospheric isotopologic water vapour distributions on a global scale.
BibTeX:
@article{HerbinHartmansTurquetyEtAl2007,
  author = {Herbin, H. and Hartmans, D. and Turquety, S. and Wespes, C. and Barret, B. and Hadji-Lazaro, J. and Clerbaux, C. and Coheur, P.-F.},
  title = {Global distributions of water vapour isotopologues retrieved from IMG/ADEOS data},
  journal = {Atmospheric Chemistry and Physics},
  year = {2007},
  volume = {7},
  pages = {3957-3968},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547469427&doi=10.5194%2facp-7-3957-2007&partnerID=40&md5=d83a24316e347028f0a352f5eb93b138},
  doi = {10.5194/acp-7-3957-2007}
}
Abstract: The design of a new apparatus, named FANTASIO, for studying jet-cooled molecules is described. It includes, around the same supersonic expansion cell, a high resolution Fourier transform spectrometer with single or multipass optics, a tunable diode laser spectrometer with optional cavity ring-down facilities, and a quadrupole mass spectrometer. Performance and operational procedures are illustrated.
BibTeX:
@article{HermanDidricheHurtmansEtAl2007,
  author = {Herman, M. and Didriche, K. and Hurtmans, D. and Kizil, B. and MacKo, P. and Rizopoulos, A. and Van Poucke, P.},
  title = {FANTASIO: A versatile experimental set-up to investigate jet-cooled molecules},
  journal = {Molecular Physics},
  year = {2007},
  volume = {105},
  pages = {815-823},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34249095743&doi=10.1080%2f00268970601063820&partnerID=40&md5=75455dd8e25c5db198331ae00d343967},
  doi = {10.1080/00268970601063820}
}
Abstract: We measured the temperature dependence of the nitrogen broadening, narrowing and line-mixing coefficients of four lines of the P9 manifold in the ν3 band of 12CH4 for atmospheric purposes. The data were collected using our tunable diode laser (TDL) spectrometer with active wavenumber control coupled to a newly developed cold Herriott cell with a path length of 5.37 m and a temperature uniformity of better than 0.01 K along the cell. We recorded and analyzed spectra recorded at sample temperatures between 90 K and room temperature. We have investigated the influence of our new results in the inversion model used to retrieve methane profiles from atmospheric spectra; our new results make it possible to retrieve significantly more precise methane profiles. The atmospheric spectra we utilized were obtained by several of us with a balloon-born Fourier Transform infrared experiment in a limb configuration. Differences up to 7% on the retrieved volume mixing ratio were found compared to an inversion model using only HITRAN04 spectroscopic parameters. © 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{MondelainPayanDengEtAl2007,
  author = {Mondelain, D. and Payan, S. and Deng, W. and Camy-Peyret, C. and Hurtmans, D. and Mantz, A.W.},
  title = {Measurement of the temperature dependence of line mixing and pressure broadening parameters between 296 and 90 K in the ν3 band of 12CH4 and their influence on atmospheric methane retrievals},
  journal = {Journal of Molecular Spectroscopy},
  year = {2007},
  volume = {244},
  pages = {130-137},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547911817&doi=10.1016%2fj.jms.2007.05.005&partnerID=40&md5=fd13ce6a89b71aa2fbb3e43e690479bd},
  doi = {10.1016/j.jms.2007.05.005}
}
Abstract: In this work we present a line profile study for air-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 vibrational bands. The room temperature spectra were recorded at a resolution of 0.008 cm-1 using a Fourier Transform spectrometer. The air-broadening, air-shift, and air-line mixing coefficients were derived from a simultaneous fitting of spectra using the Voigt model and a Speed-Dependent Voigt lineshape model. The results obtained are consistent with other studies in addition to the theoretically calculated values. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws were used to calculate the relaxation matrix elements. © 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{Predoi-CrossLiuHolladayEtAl2007,
  author = {Predoi-Cross, A. and Liu, W. and Holladay, C. and Unni, A.V. and Schofield, I. and McKellar, A.R.W. and Hurtmans, D.},
  title = {Line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide perturbed by air},
  journal = {Journal of Molecular Spectroscopy},
  year = {2007},
  volume = {246},
  pages = {98-112},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35348985908&doi=10.1016%2fj.jms.2007.08.008&partnerID=40&md5=ccc6dd5c612b2c5d0bd92db2be4f64e6},
  doi = {10.1016/j.jms.2007.08.008}
}
Abstract: Transitions of pure carbon dioxide have been measured using a Fourier transform spectrometer in the 30012 ← 00001 and 30013 ← 00001 vibrational bands. The room temperature spectra, recorded at a resolution of 0.008 cm-1, were analyzed using the Voigt model and a Speed Dependent Voigt line shape model that includes a pressure dependent narrowing parameter. Intensities, self-induced pressure broadening, shifts, and weak line mixing coefficients are determined. The results obtained are consistent with other studies in addition to the theoretically calculated values. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws were used to calculate the relaxation matrix elements. © 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{Predoi-CrossUnniLiuEtAl2007,
  author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.},
  title = {Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing, and speed dependence},
  journal = {Journal of Molecular Spectroscopy},
  year = {2007},
  volume = {245},
  pages = {34-51},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548384855&doi=10.1016%2fj.jms.2007.07.004&partnerID=40&md5=caad6105e5e8f3e4534cef5ade627881},
  doi = {10.1016/j.jms.2007.07.004}
}
Abstract: The Microwave Limb Sounder on Aura has produced an extensive set of measurement of CO in the middle atmosphere. The measurements are usable for scientific studies from the upper troposphere up to 90 km altitude. We describe these measurements and validate them by demonstrating their internal consistency and by comparing them to other remotely sounded measurements and to 2-D model simulations. Comparisons with other measurements suggest that MLS has a positive bias of 25-50% in the mesosphere and a negative bias of up to 70% in the (almost CO-free) lower stratosphere. The geophysical features observed in the MLS CO field show excellent qualitative agreement with other measurements. Copyright 2007 by the American Geophysical Union.
BibTeX:
@article{PumphreyFilipiakLiveseyEtAl2007,
  author = {Pumphrey, H.C. and Filipiak, M.J. and Livesey, N.J. and Schwartz, M.J. and Boone, C. and Walker, K.A. and Bernath, P. and Ricaud, P. and Barret, B. and Clerbaux, C. and Jarnot, R.F. and Manney, G.L. and Waters, J.W.},
  title = {Validation of middle-atmosphere carbon monoxide retrievals from the Microwave Limb Sounder on Aura},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2007},
  volume = {112},
  article number = {D24S38},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-49249090630&doi=10.1029%2f2007JD008723&partnerID=40&md5=2e59bed67eefeb501758c074c526bd8c},
  doi = {10.1029/2007JD008723}
}
Abstract: We highlight chemistry and trend measurements from the Atmospheric Chemistry Experiment (ACE) which is providing precise middle troposphere to the lower thermosphere measurements of the Earth's upper troposphere to lower mesosphere with the solar occultation technique. The primary instrument is a 0.02 cm -1 resolution Fourier transform spectrometer covering 750-4400 cm -1 simultaneously. ACE also known as SCISAT 1 is a Canadian lead mission launched into a 74° inclined orbit at 650 km altitude on August 12, 2003 by a U.S.-supplied Pegasus vehicle. Additional measurements are obtained with a UV-visible spectrometer and two imagers providing measurements at 0.525 and 1.02 microns.
BibTeX:
@conference{RinslandBernathBooneEtAl2007,
  author = {Rinsland, C.P. and Bernath, P. and Boone, C. and Nassar, R. and Dufour, G. and Clerbaux, C.},
  title = {Atmospheric Chemistry Experiment (ACE) measurements of the upper troposphere and stratosphere},
  journal = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858467679&partnerID=40&md5=196b5a52cd62c7d7053159fd02ded55c}
}
Abstract: We report measurements of hydrogen peroxide (H2O2) profiles from infrared solar occultation spectra recorded at 0.02 cm-1 resolution by the atmospheric chemistry experiment (ACE) during 2004 and 2005. Mixing ratios as high as 1.7 ppbv (1 ppbv=1×10-9 per unit volume) were measured in the subtropical troposphere. Back trajectories, fire count statistics, and simultaneous measurements of other species from the same occultation provide evidence that the elevated H2O2 mixing ratios originated from a young biomass-burning plume. The ACE time series show only a few cases with elevated H2O2 mixing ratios likely because of the short lifetime of H2O2 and the limited sampling during biomass-burning time periods. © 2007 Elsevier Ltd. All rights reserved.
BibTeX:
@article{RinslandCoheurHerbinEtAl2007,
  author = {Rinsland, C.P. and Coheur, P.F. and Herbin, H. and Clerbaux, C. and Boone, C. and Bernath, P. and Chiou, L.S.},
  title = {Detection of elevated tropospheric hydrogen peroxide (H2O2) mixing ratios in atmospheric chemistry experiment (ACE) subtropical infrared solar occultation spectra},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2007},
  volume = {107},
  pages = {340-348},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250207571&doi=10.1016%2fj.jqsrt.2007.02.009&partnerID=40&md5=0ce99534916b1ef4cfb25396e29f5e23},
  doi = {10.1016/j.jqsrt.2007.02.009}
}
Abstract: Simultaneous ACE (Atmospheric Chemistry Experiment) upper tropospheric CO, C2H6, HCN, CH3Cl, CH4, C2H2, CH3OH, HCOOH, and OCS measurements show plumes up to 185 ppbv (10-9 per unit volume) for CO, 1.36 ppbv for C2H6, 755 pptv (10-12 per unit volume) for HCN, 1.12 ppbv for CH3Cl, 1.82 ppmv (10-6 per unit volume) for CH4, 0.178 ppbv for C2H2, 3.89 ppbv for CH3OH, 0.843 ppbv for HCOOH, and 0.48 ppbv for OCS in western Canada and Alaska at 50°N-68°N latitude between 29 June and 23 July 2004. Enhancement ratios and emission factors for HCOOH, CH3OH, HCN, C2H6, and OCS relative to CO at 250-350 hPa are inferred from measurements of young plumes compared with lower mixing ratios assumed to represent background conditions based on a CO emission factor derived from boreal measurements. Results are generally consistent with the limited data reported for various vegetative types and emission phases measured in extratropical forests including boreal forests. The low correlation between fire product emission mixing ratios and the SF6 mixing ratio is consistent with no significant SF6 emissions from the biomass fires. Copyright 2007 by the American Geophysical Union.
BibTeX:
@article{RinslandDufourBooneEtAl2007,
  author = {Rinsland, C.P. and Dufour, G. and Boone, C.D. and Bernath, P.F. and Chiou, L. and Coheur, P.-F. and Turquety, S. and Clerbaux, C.},
  title = {Satellite boreal measurements over Alaska and Canada during June-July 2004: Simultaneous measurements of upper tropospheric CO, C2H6, HCN, CH3Cl, CH4, C2H2, CH3OH, HCOOH, OCS, and SF6 mixing ratios},
  journal = {Global Biogeochemical Cycles},
  year = {2007},
  volume = {21},
  article number = {GB3008},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35648937741&doi=10.1029%2f2006GB002795&partnerID=40&md5=edccade2fb3c4e4619317a66e1ecbee6},
  doi = {10.1029/2006GB002795}
}
Abstract: We present measurements of He-broadening parameters for the R(0) and P(2) lines in the fundamental band of 13CO at different temperatures between 12 K and room temperature. The broadening parameters are determined, taking into account confinement narrowing, by simultaneous least-squares fitting of spectra recorded using a frequency stabilized diode laser spectrometer. The pressure broadening cross sections are deduced and compared to close-coupling calculations and earlier results obtained for rotational transitions of 12CO. © 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{ThibaultMantzClaveauEtAl2007,
  author = {Thibault, F. and Mantz, A.W. and Claveau, C. and Henry, A. and Valentin, A. and Hurtmans, D.},
  title = {Broadening of the R(0) and P(2) lines in the 13CO fundamental by helium atoms from 300 K down to 12 K: Measurements and comparison with close-coupling calculations},
  journal = {Journal of Molecular Spectroscopy},
  year = {2007},
  volume = {246},
  pages = {118-125},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35348943982&doi=10.1016%2fj.jms.2007.09.001&partnerID=40&md5=4ef9c79f560b8e192b97ef0de0a74492},
  doi = {10.1016/j.jms.2007.09.001}
}
Abstract: Assignment of an HDO line list extracted from a recently measured H2O/HDO/D2O Fourier transform absorption spectrum recorded in the 11 600-23 000 cm-1 region by Bach et al. (M. Bach, S. Fally, P.-F. Coheur, M. Carleer, A. Jenouvrier, A.C. Vandaele, J. Mol. Spectrosc. 232 (2005) 341-350.) is presented. More than 94% of the 3256 lines are given quantum number assignments and ascribed to line absorption by HDO; most of the remaining lines are actually due to D2O. High accuracy variational predictions of line positions and intensities are used for the spectral assignment process. Assignments to the ν1 + 5ν3, 2ν2 + 5ν3, ν1 + ν2 + 3ν3 and ν1 + 6ν3 bands are presented for the first time. Comparisons are made with published ICLAS spectra covering the same spectral region and suggestions made for its recalibration. The results are used to illustrate the dynamical behaviour of highly excited vibrational states of HDO and to discuss previous vibrational assignments to high lying rotation-vibration states of this system. © 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{VoroninNaumenkoCarleerEtAl2007,
  author = {Voronin, B.A. and Naumenko, O.V. and Carleer, M. and Coheur, P.-F. and Fally, S. and Jenouvrier, A. and Tolchenov, R.N. and Vandaele, A.C. and Tennyson, J.},
  title = {HDO absorption spectrum above 11 500 cm-1: Assignment and dynamics},
  journal = {Journal of Molecular Spectroscopy},
  year = {2007},
  volume = {244},
  pages = {87-101},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547111593&doi=10.1016%2fj.jms.2007.03.008&partnerID=40&md5=3e56f26b3857a1fdedd2ef459e8e77f7},
  doi = {10.1016/j.jms.2007.03.008}
}
Abstract: Global distributions of nitric acid (HNO3) partial columns in the troposphere and the stratosphere are shown for the first time. HNO3 vertical profiles are retrieved from a set of high-resolution infrared spectra, measured by the nadir-viewing Interferometric Monitor for Greenhouse Gases (IMG) instrument onboard the ADEOS satellite. Ten successive days of IMG operation in April 1997 are analyzed, yielding quasi-global distributions. We show that the IMG measurements contain between 0.7 and 1.8 independent pieces of information on the HNO3 vertical distribution; the extent of which depends on the observed scene. In the tropics and the midlatitudes, tropospheric and stratospheric columns can be separated, whereas, in the colder polar regions, the total column is the most relevant quantity. A detailed error budget reveals that the accuracy on the profile measurements ranges from 5-15% in the stratosphere to about 20-30% in the middle troposphere, and as much as 60% in the lowermost troposphere where the measurements are less sensitive. The global distributions of tropospheric and stratospheric partial columns are presented and discussed. In the stratosphere we measure higher columns at both poles than in the intertropical belt, as expected for the period in April analyzed here. In the troposphere, the zonal distributions show elevated values nearby NOx source regions, such as central Europe, the Eastern coast of the United States, and the North-West of India. Typical profiles with mixing ratios up to 2 ppbv in the boundary layer and 1 ppbv in the free troposphere are identified. These novel results indicate a possible role of HNO3 in the long-range transport of active nitrogen and open promising perspectives for future space missions dedicated to atmospheric chemistry. Copyright 2007 by the American Geophysical Union.
BibTeX:
@article{WespesHurtmansHerbinEtAl2007,
  author = {Wespes, C. and Hurtmans, D. and Herbin, H. and Barret, B. and Turquety, S. and Hadji-Lazaro, J. and Clerbaux, C. and Coheur, P.-F.},
  title = {First global distributions of nitric acid in the troposphere and the stratosphere derived from infrared satellite measurements},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2007},
  volume = {112},
  article number = {D13311},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548603241&doi=10.1029%2f2006JD008202&partnerID=40&md5=d3f1a64eb5e7c367bd4e5fb6024c8844},
  doi = {10.1029/2006JD008202}
}
Abstract: Chlorophyll a retrieval from satellite is based on algorithms that convert the phytoplankton absorption into chlorophyll a by means of the specificphytoplankton absorption. This factor has been found to be highly variable, spatially and seasonally. The variability of the chlorophyll a-specific phytoplankton absorption in Belgian waters (Southern North Sea) was investigated to determine how it is affecting the chlorophyll a retrieval from satellite information. The Southern Bight of the North Sea is a very dynamic area influenced by river discharges and characterised by highly variable chlorophyll, suspended matter and coloured dissolved organic matter absorption. The impact of using a mean value of specificphytoplankton absorption as usually done instead of the real one in chlorophyll a retrieval was estimated and found to be significant (underestimation up to 70% at 665 nm).
BibTeX:
@conference{AstorecaRousseauLancelot2006,
  author = {Astoreca, R. and Rousseau, V. and Lancelot, C.},
  title = {Specific phytoplankton absorption variability and implication for chlorophyll a retrieval in Belgian waters (Southern North Sea)},
  journal = {European Space Agency, (Special Publication) ESA SP},
  year = {2006},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749184359&partnerID=40&md5=122f4cae49d61f79ab90962113c186fe}
}
Abstract: Relating to a conjecture on the decomposability of positive maps in 3 ⊗ 3, we solve the open problem of the existence of (5, 5) and (6, 6) PPT edge states. © 2006 Elsevier B.V. All rights reserved.
BibTeX:
@article{Clarisse2006,
  author = {Clarisse, L.},
  title = {Construction of bound entangled edge states with special ranks},
  journal = {Physics Letters, Section A: General, Atomic and Solid State Physics},
  year = {2006},
  volume = {359},
  pages = {603-607},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750321394&doi=10.1016%2fj.physleta.2006.07.045&partnerID=40&md5=6871f41c8105d21f2cd291e2f3aeacc4},
  doi = {10.1016/j.physleta.2006.07.045}
}
Abstract: Robustness measures as introduced by Vidal and Tarrach (1999 Robustness of entanglement Phys. Rev. A 59 141-55) quantify the extent to which entangled states remain entangled under mixing. Analogously, we introduce here the Schmidt robustness and the random Schmidt robustness. The latter notion is closely related to the construction of Schmidt balls around the identity. We analyse the situation for pure states and provide nontrivial upper and lower bounds. Upper bounds to the random Schmidt-2 robustness allow us to construct a particularly simple distillability criterion. We present two conjectures, the first one is related to the radius of inner balls around the identity in the convex set of Schmidt number n-states. We also conjecture a class of optimal Schmidt witnesses for pure states. © 2006 IOP Publishing Ltd.
BibTeX:
@article{Clarisse2006a,
  author = {Clarisse, L.},
  title = {On the Schmidt robustness of pure states},
  journal = {Journal of Physics A: Mathematical and General},
  year = {2006},
  volume = {39},
  pages = {4239-4249},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645680221&doi=10.1088%2f0305-4470%2f39%2f16%2f010&partnerID=40&md5=408501ae5e2f4b125c5308c1b9e2b7ad},
  doi = {10.1088/0305-4470/39/16/010}
}
Abstract: An important open problem in quantum information theory is the question of the existence of NPT bound entanglement. In the past years, little progress has been made, mainly because of the lack of mathematical tools to address the problem, (i) In an attempt to overcome this, we show how the distillability problem can be reformulated as a special instance of the separability problem, for which a large number of tools and techniques are available. (ii) Building up to this we also show how the problem can be formulated as a Schmidt number problem. (iii) A numerical method for detecting distillability is presented and strong evidence is given that all 1-copy undistillable Werner states are also 4-copy undistillable. (iv) The same method is used to estimate the volume of distillable states, and the results suggest that bound entanglement is primarily a phenomenon found in low dimensional quantum systems. (v) Finally, a set of one parameter states is presented which we conjecture to exhibit all forms of distillability. © Rinton Press.
BibTeX:
@article{Clarisse2006b,
  author = {Clarisse, L.},
  title = {The distillability problem revisited},
  journal = {Quantum Information and Computation},
  year = {2006},
  volume = {6},
  pages = {539-560},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33746925640&partnerID=40&md5=0f72f6ae6d4914149baef83c637e719e}
}
Abstract: Recently, P. Wocjan and M. Horodecki [Open Syst. Inf. Dyn. 12, 331 (2005)] gave a characterization of combinatorially independent permutation separability criteria. Combinatorial independence is a necessary condition for permutations to yield truly independent criteria meaning that no criterion is strictly stronger that any other. In this paper we observe that some of these criteria are still dependent and analyze why these dependencies occur. To remove them we introduce an improved necessary condition and give a complete classification of the remaining permutations. We conjecture that the remaining class of criteria only contains truly independent permutation separability criteria. Our conjecture is based on the proof that for two, three and four parties all these criteria are truly independent and on numerical verification of their independence for up to 8 parties. It was commonly believed that for three parties there were 9 independent criteria, here we prove that there are exactly 6 independent criteria for three parties and 22 for four parties. © Rinton Press.
BibTeX:
@article{ClarisseWocjan2006,
  author = {Clarisse, L. and Wocjan, P.},
  title = {On independent permutation separability criteria},
  journal = {Quantum Information and Computation},
  year = {2006},
  volume = {6},
  pages = {277-288},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645782295&partnerID=40&md5=8fa2942cc6d173d917fa42e469015fee}
}
Abstract: We propose to combine the tropospheric measurements provided by the IASI and GOME2 instruments aboard METOP, together with data from ground-based stations, airborne and spaceborne remote sensors, along with atmospheric chemistry models (CTMs) in order to improve our knowledge of processes constraining the chemical composition of the troposphere and to study the regional and global scale air quality. The measurements of ozone (O 3), carbon monoxide (CO), nitrogen dioxide (NO2), formaldehyde (CH2O), and methane (CH4) will be used in conjunction with the 3D tropospheric LMDz-INCA, MOZART, IMAGES and CHIMERE CTM models, using data assimilation and inversion modeling techniques, to study the global distribution of these species and to derive improved emissions estimates. Before the METOP launch, all the tools developed in the framework of this project will be used to analyse the AURA TES and OMI tropospheric products. After the launch of METOP, the data provided by both satellites will then be analyzed with the CTMs. The resulting global distributions will be used to perform detailed studies of the role of biomass burning in the budget of tropospheric species, the emissions of ozone precursors, the role of convective transport of pollutants, and its consequences in terms of air quality.
BibTeX:
@conference{ClerbauxTurquetyHadji-LazaroEtAl2006,
  author = {Clerbaux, C. and Turquety, S. and Hadji-Lazaro, J. and Granier, C. and Hauglustaine, D. and Laval, S.S. and Beekmann, M. and Orphal, J. and Bergametti, G. and Camy-Peyret, C. and Payan, S. and Coheur, P. and De Mazière, M. and Müller, J.-F. and Prunet, P. and Klonecki, A.},
  title = {French/belgian scientific contribution to tropospheric studies using the metop sensors},
  journal = {European Space Agency, (Special Publication) ESA SP},
  year = {2006},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84888847002&partnerID=40&md5=59cd320f54d447c27a9b01b0096a668b}
}
Abstract: A non-empirical algorithm is presented to retrieve the optical depth in the 750-1250 cm -1 spectral range, of aerosol located in the boundary layer over the ocean, from nadir high-resolution radiance spectra in the thermal infrared. The algorithm is based on a line-by-line radiative transfer forward model and used the Optimal Estimation Method for the retrieval. Its performance strongly depends on the quality of the a priori temperature and H 2 O atmospheric profiles. To demonstrate the relevance of the algorithm, distributions of maritime aerosol parameters have been retrieved from IMG/ADEOS data for December 1996, using the algorithm with the LBLRTM radiative transfer code, and ERA40 (ECMWF) a priori atmospheric profiles and surface conditions. © 2005 COSPAR.
BibTeX:
@article{KruglanskiDeMaziereVandaeleEtAl2006,
  author = {Kruglanski, M. and De Mazière, M. and Vandaele, A.C. and Hurtmans, D.},
  title = {Boundary layer aerosol retrieval from thermal infrared nadir sounding - Preliminary results},
  journal = {Advances in Space Research},
  year = {2006},
  volume = {37},
  pages = {2160-2165},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745737199&doi=10.1016%2fj.asr.2005.08.032&partnerID=40&md5=026f7de99489eace0cfba8c3bf351d2f},
  doi = {10.1016/j.asr.2005.08.032}
}
Abstract: Total chlorine (CITOT) in the stratosphere has been determined using the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) measurements of HCl, ClONO2, CH3Cl, CCl4, CCl3F (CFC-11), CCl2F2 (CFC-12), CHClF2 (HCFC-22), CCl2FCClF2 (CFC-113), CH3CClF2 (HCFC-142b), COClF, and ClO supplemented by data from several other sources, including both measurements and models. Separate chlorine inventories were carried out in five latitude zones (60°-82°N, 30°-60°N, 30°S-30°N, 30°-60°S, and 60°-82°S), averaging the period of February 2004 to January 2005 inclusive, when possible, to deal with seasonal variations. The effect of diurnal variation was avoided by only using measurements taken at local sunset. Mean stratospheric ClTOT values of 3.65 ppbv were determined for both the northern and southern midlatitudes (with an estimated 1σ, accuracy of ±0.13 ppbv and a precision of ±.09 ppbv), accompanied by a slightly lower value in the tropics and slightly higher values at high latitudes. Stratospheric ClTOT profiles in all five latitude zones are nearly linear with a slight positive slope in ppbv /km. Both the observed slopes and pattern of latitudinal variation can be interpreted as evidence of the beginning of a decline in global stratospheric chlorine, which is qualitatively consistent with the mean stratospheric circulation pattern and time lag necessary for transport. Copyright 2006 by the American Geophysical Union.
BibTeX:
@article{NassarBernathBooneEtAl2006,
  author = {Nassar, R. and Bernath, P.F. and Boone, C.D. and Clerbaux, C. and Coheur, P.F. and Dufour, G. and Froidevaux, L. and Mahieu, E. and McConnell, J.C. and McLeod, S.D. and Murtagh, D.P. and Rinsland, C.P. and Semeniuk, K. and Skelton, R. and Walker, K.A. and Zander, R.},
  title = {A global inventory of stratospheric chlorine in 2004},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2006},
  volume = {111},
  article number = {D22312},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548551528&doi=10.1029%2f2006JD007073&partnerID=40&md5=6edce05c44317e8accf69d61214d1344},
  doi = {10.1029/2006JD007073}
}
BibTeX:
@conference{RinslandBernathBooneEtAl2006,
  author = {Rinsland, C. and Bernath, P. and Boone, C. and Clerbaux, C. and Turquety, S.},
  title = {Upper tropospheric measurements of biomass burning emissions with the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer},
  journal = {European Space Agency, (Special Publication) ESA SP},
  year = {2006},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749182522&partnerID=40&md5=0de08ff8acc9b1ad76a22ca7842f5603}
}
Abstract: The first space-based measurements of upper tropospheric (110-300 hPa) formic acid (HCOOH) are reported from 0.02 cm-1 resolution Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer solar occultation measurements at 16°S-43°S latitude during late September to early October in 2004 and 2005. A maximum upper tropospheric HCOOH mixing ratio of 3.13 ± 0.02 ppbv (1 ppbv = 10-9 per unit volume), 1 sigma, at 10.5 km altitude was measured during 2004 at 29.97°S latitude and a lower maximum HCOOH mixing ratio of 2.03 ± 0.28 ppbv, at 9.5 km altitude was measured during 2005. Fire counts, back trajectories, and correlations of HCOOH mixing ratios with ACE simultaneous measurements of other fire products confirm the elevated HCOOH mixing ratios originated primarily from tropical fire emissions. A HCOOH emission factor relative to CO of 1.99 ± 1.34 g kg-1 during 2004 in upper tropospheric plumes is inferred from a comparison with lower mixing ratios measured during the same time period assuming HITRAN 2004 spectroscopic parameters. Copyright 2006 by the American Geophysical Union.
BibTeX:
@article{RinslandBooneBernathEtAl2006,
  author = {Rinsland, C.P. and Boone, C.D. and Bernath, P.F. and Mahieu, E. and Zander, R. and Dufour, G. and Clerbaux, C. and Turquety, S. and Chiou, L. and McConnell, J.C. and Neary, L. and Kaminski, J.W.},
  title = {First space-based observations of formic acid (HCOOH): Atmospheric Chemistry Experiment austral spring 2004 and 2005 Southern Hemisphere tropical-mid-latitude upper tropospheric measurements},
  journal = {Geophysical Research Letters},
  year = {2006},
  volume = {33},
  article number = {L23804},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250216582&doi=10.1029%2f2006GL027128&partnerID=40&md5=fff55e637afd0b3f794a61e83a1e9e66},
  doi = {10.1029/2006GL027128}
}
Abstract: An emission spectrum recorded in an oxyacetylene torch [P.-F. Coheur, P.F. Bernath, M. Carleer, R. Colin, O.L. Polyansky, N.F. Zobov, S.V. Shirin, R.J. Barber, J. Tennyson, J. Chem. Phys. 122 (2005) 074307] is analyzed for the region covering stretching fundamentals and associated hot bands of water. Many lines could be assigned on the basis of previously determined energy levels. New assignments made with a new variational linelist allow a further 800 energy levels covering 15 vibrational states and rotations up to J = 32 to be assigned. A simultaneous re-analysis of previously reported sunspot absorption spectra leads to the assignment of 581 further lines in the L-band spectrum and 67 in the N-band spectrum. © 2006 Elsevier Inc. All rights reserved.
BibTeX:
@article{ZobovShirinPolyanskyEtAl2006,
  author = {Zobov, N.F. and Shirin, S.V. and Polyansky, O.L. and Barber, R.J. and Tennyson, J. and Coheur, P.-F. and Bernath, P.F. and Carleer, M. and Colin, R.},
  title = {Spectrum of hot water in the 2000-4750 cm-1 frequency range},
  journal = {Journal of Molecular Spectroscopy},
  year = {2006},
  volume = {237},
  pages = {115-122},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646199805&doi=10.1016%2fj.jms.2006.03.001&partnerID=40&md5=b209b3b72157cb4d5dfa88582ec6bcd0},
  doi = {10.1016/j.jms.2006.03.001}
}
Abstract: The Southern Bight of the North Sea is characterised by a large influence of river inputs, which results in eutrophication of the area. High concentrations of plankton biomass and suspended matter have been reported for this area, in relation with blooms of different species and resuspension of bottom sediments. In spring the haptophyte Phaeocystis globosa blooms throughout the area reaching up to 30 mg Chlorophyll m-3 or more nearshore. This event is followed in June by red tides of the dinoflagellate Noctiluca scintillans. These blooms are concurrent with different species of diatoms. The strong optical signature of these blooms is clear to human observers making them potentially detectable in satellite imagery. As a first step in this direction, sampling has been carried out in the area, during Phaeocystis and Noctiluca blooms in 2003 and 2004. Phytoplankton pigments and inherent optical properties (particle, detrital and phytoplankton absorption) have been measured spectrophotometrically, and in situ using an ac-9 for total absorption and particle scattering. Field data were compared with optical properties of pure species obtained in laboratory. In parallel, water-leaving reflectance has been also measured. In this paper we characterise the optical signatures of diatoms, Phaeocystis and Noctiluca and their contribution to total absorption. The impact on water-leaving reflectance spectra is evaluated; in order to assess the conditions in which remote sensing can provide information for monitoring the timing, extent and magnitude of blooms in this coastal area.
BibTeX:
@conference{AstorecaRousseauRuddickEtAl2005,
  author = {Astoreca, R. and Rousseau, V. and Ruddick, K. and Van Mol, B. and Parent, J.-Y. and Lancelot, C.},
  title = {Optical properties of algal blooms in an eutrophicated coastal area and its relevance to remote sensing},
  journal = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2005},
  volume = {5885},
  article number = {58850V},
  pages = {1-11},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-29244439584&doi=10.1117%2f12.615160&partnerID=40&md5=0ff9c80ef2da6feb5f506b1f55135f58},
  doi = {10.1117/12.615160}
}
Abstract: This work presents new measurements of HDO line parameters in the near-infrared and visible regions (11 500-23 000 cm-1). The measurements consist in high-resolution Fourier transform absorption spectra of H2O/HDO/D2O vapor mixtures, obtained using a long absorption path. Spectra with and without nitrogen as the buffer gas were recorded. Due to the simultaneous presence of the three isotopologues H 2O, D2O, and HDO, the H2O lines removal and the D2O lines identification were two necessary preliminary steps to derive the HDO line parameters. The D2O contribution was small and confined to the well-known 4ν1 + ν3 band. An extensive listing of HDO spectroscopic parameters was obtained, for the first time, by fitting some 3256 observed lines to Voigt line profiles. The list contains calibrated line positions, absorption cross-sections and, for many of the lines, N2-broadening coefficients, as well as N 2-induced frequency shifts. As a result of the low HDO vapor pressures, it was not possible to retrieve the self-broadening parameters. The list is available on the http://www.ulb.ac.be/cpm website. © 2005 Elsevier Inc. All rights reserved.
BibTeX:
@article{BachFallyCoheurEtAl2005,
  author = {Bach, M. and Fally, S. and Coheur, P.-F. and Carleer, M. and Jenouvrier, A. and Vandaele, A.C.},
  title = {Line parameters of HDO from high-resolution Fourier transform spectroscopy in the 11 500-23 000 cm-1 spectral region},
  journal = {Journal of Molecular Spectroscopy},
  year = {2005},
  volume = {232},
  pages = {341-350},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-21844460571&doi=10.1016%2fj.jms.2005.04.018&partnerID=40&md5=b72c87ed0c8dd902a8a4d67e46dbb002},
  doi = {10.1016/j.jms.2005.04.018}
}
Abstract: Collision-induced line narrowing, which has been discovered in the 1950s and investigated thoroughly in the laboratory since then, has yet never been taken into account in the spectroscopic remote sensing of the atmosphere. This work investigates the effect of collision-induced line narrowing onto the retrieval of HCl and HF vertical profiles from ground-based solar absorption FTIR measurements made at the NDSC station of the Jungfraujoch (46.5°N, 8°E and 3580 m above see level). The retrievals are performed with the Atmosphit software, recently developed at the Université Libre de Bruxelles. It is presented in this paper for the first time and is validated against the widely used SFIT2 software. The impact of the line narrowing onto the retrieval of HCl and HF vertical profiles is examined relying on careful information content and error budget analyses. We report that the effect is relatively weak for HCl but significant for HF. Confirmation of the need to take the line narrowing into account for the retrieval of vertical profiles from ground-based FTIR spectra is given by comparison with data from the HALOE space borne instrument, rather insensitive to this spectroscopic effect. © 2005 Elsevier Ltd. All rights reserved.
BibTeX:
@article{BarretHurtmansCarleerEtAl2005,
  author = {Barret, B. and Hurtmans, D. and Carleer, M.R. and De Mazière, M. and Mahieu, E. and Coheur, P.-F.},
  title = {Line narrowing effect on the retrieval of HF and HCl vertical profiles from ground-based FTIR measurements},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2005},
  volume = {95},
  pages = {499-519},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18844432324&doi=10.1016%2fj.jqsrt.2004.12.005&partnerID=40&md5=9078da6e4dcb653b2adb3ddc07e7af49},
  doi = {10.1016/j.jqsrt.2004.12.005}
}
Abstract: This paper presents the first global distributions of CO vertical profiles retrieved from a thermal infrared FTS working in the nadir geometry. It is based on the exploitation of the high resolution and high quality spectra measured by the Interferometric Monitor of Greenhouse gases (IMG) which flew onboard the Japanese ADEOS platform in 1996-1997. The retrievals are performed with an algorithm based on the Optimal Estimation Method (OEM) and are characterized in terms of vertical sensitivity and error budget. It is found that most of the IMG measurements contain between 1.5 and 2.2 independent pieces of information about the vertical distribution of CO from the lower troposphere to the upper troposphere-lower stratosphere (UTLS). The retrievals are validated against coincident NOAA/CMDL in situ surface measurements and NDSC/FTIR total columns measurements. The retrieved global distributions of CO are also found to be in good agreement with the distributions modeled by the GEOS-CHEM 3D CTM, highlighting the ability of IMG to capture the horizontal as well as the vertical structure of the CO distribution. © 2005 Author(s). This work is licensed under a Creative Commons License.
BibTeX:
@article{BarretTurquetyHurtmansEtAl2005,
  author = {Barret, B. and Turquety, S. and Hurtmans, D. and Clerbaux, C. and Hadji-Lazaro, J. and Bey, I. and Auvray, M. and Coheur, P.-F.},
  title = {Global carbon monoxide vertical distributions from spaceborne high-resolution FTIR nadir measurements},
  journal = {Atmospheric Chemistry and Physics},
  year = {2005},
  volume = {5},
  pages = {2901-2914},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-26944478377&doi=10.5194%2facp-5-2901-2005&partnerID=40&md5=263108546e0d44bc7443b041d5ec0c11},
  doi = {10.5194/acp-5-2901-2005}
}
Abstract: SCISAT-1, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003. The primary ACE instrument is a high spectral resolution (0.02 cm-1) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 μm (750-4400 cm-1). The satellite also features a dual spectrophotometer known as MAESTRO with wavelength coverage of 285-1030 nm and spectral resolution of 1-2 nm. A pair of filtered CMOS detector arrays records images of the Sun at 0.525 and 1.02 μm. Working primarily in solar occultation, the satellite provides altitude profile information (typically 10-100 km) for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest, as well as atmospheric extinction profiles over the latitudes 85°N to 85°S. This paper presents a mission overview and some of the first scientific results. Copyright 2005 by the American Geophysical Union.
BibTeX:
@article{BernathMcElroyAbramsEtAl2005,
  author = {Bernath, P.F. and McElroy, C.T. and Abrams, M.C. and Boone, C.D. and Butler, M. and Camy-Peyret, C. and Carleer, M. and Clerbaux, C. and Coheur, P.-F. and Colin, R. and DeCola, P. and DeMazière, M. and Drummond, J.R. and Dufour, D. and Evans, W.F.J. and Fast, H. and Fussen, D. and Gilbert, K. and Jennings, D.E. and Llewellyn, E.J. and Lowe, R.P. and Mahieu, E. and McConnell, J.C. and McHugh, M. and McLeod, S.D. and Michaud, R. and Midwinter, C. and Nassar, R. and Nichitiu, F. and Nowlan, C. and Rinsland, C.P. and Rochon, Y.J. and Rowlands, N. and Semeniuk, K. and Simon, P. and Skelton, R. and Sloan, J.J. and Soucy, M.-A. and Strong, K. and Tremblay, P. and Turnbull, D. and Walker, K.A. and Walkty, I. and Wardle, D.A. and Wehrle, V. and Zander, R. and Zou, J.},
  title = {Atmospheric chemistry experiment (ACE): Mission overview},
  journal = {Geophysical Research Letters},
  year = {2005},
  volume = {32},
  article number = {L15S01},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-25844526462&doi=10.1029%2f2005GL022386&partnerID=40&md5=36c3d1b87b5d42c8afaf63075095d4b2},
  doi = {10.1029/2005GL022386}
}
Abstract: A necessary and sufficient condition for one-distillability is formulated in terms of decomposable positive maps. As an application we provide insight into why all states violating the reduction criterion map are distillable and demonstrate how to construct such maps in a systematic way. We establish a connection between a number of existing results, which leads to an elementary proof for the characterization of distillability in terms of two-positive maps. ©2005 The American Physical Society.
BibTeX:
@article{Clarisse2005,
  author = {Clarisse, L.},
  title = {Characterization of distillability of entanglement in terms of positive maps},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2005},
  volume = {71},
  article number = {032332},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18544388060&doi=10.1103%2fPhysRevA.71.032332&partnerID=40&md5=f9a74353cbda149028494b4437cb1289},
  doi = {10.1103/PhysRevA.71.032332}
}
Abstract: The notion of entangling power of unitary matrices was introduced by Zanardi, [Phys. Rev. A 62, 030301 (2000)]. We study the entangling power of permutations, given in terms of a combinatorial formula. We show that the permutation matrices with zero entangling power are, up to local unitaries, the identity and the swap. We construct the permutations with the minimum nonzero entangling power for every dimension. With the use of orthogonal latin squares, we construct the permutations with the maximum entangling power for every dimension. Moreover, we show that the value obtained is maximum over all unitaries of the same dimension, with a possible exception for 36. Our result enables us to construct generic examples of 4-qudit maximally entangled states for all dimensions except for 2 and 6. We numerically classify, according to their entangling power, the permutation matrices of dimensions 4 and 9, and we give some estimates for higher dimensions. © 2005 The American Physical Society.
BibTeX:
@article{ClarisseGhoshSeveriniEtAl2005,
  author = {Clarisse, L. and Ghosh, S. and Severini, S. and Sudbery, A.},
  title = {Entangling power of permutations},
  journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
  year = {2005},
  volume = {72},
  article number = {012314},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-27144461643&doi=10.1103%2fPhysRevA.72.012314&partnerID=40&md5=b6bfa17a403d9f785267871780ac1160},
  doi = {10.1103/PhysRevA.72.012314}
}
Abstract: This paper presents a comprehensive analysis of the CO observations acquired during the first eight months (January to September 2004) of the ACE mission. We show that the ACE high-resolution Fourier transform spectrometer (ACE-FTS), which operates in the solar occultation geometry and covers a wide spectral interval in the infrared, provides useful measurements in both the CO 1-0 and 2-0 vibrational bands. Vertically-resolved CO concentration profiles are retrieved, extending from the mid-troposphere to the thermosphere (from about 5 to 110 km). We have analyzed the latitudinal variability of the measurements, from which various physical and chemical atmospheric processes are highlighted for further study. Copyright 2005 by the American Geophysical Union.
BibTeX:
@article{ClerbauxCoheurHurtmansEtAl2005,
  author = {Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Barret, B. and Carleer, M. and Colin, R. and Semeniuk, K. and McConnell, J.C. and Boone, C. and Bernath, P.},
  title = {Carbon monoxide distribution from the ACE-FTS solar occultation measurements},
  journal = {Geophysical Research Letters},
  year = {2005},
  volume = {32},
  article number = {L16S01},
  pages = {1-4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-25844519524&doi=10.1029%2f2005GL022394&partnerID=40&md5=036d16efa3b27ecf0661489a15696c0e},
  doi = {10.1029/2005GL022394}
}
Abstract: This paper presents the first retrievals and validations of ozone vertical distributions from a set of high-resolution nadir thermal infrared measurements. These were obtained by the Interferometric Monitor for Greenhouse gases (IMG) instrument, which has operated on board the Japanese ADEOS platform between 1996 and 1997. The Optimal Estimation Method is used for the retrievals, along with a priori profile and covariance matrix built from model climatologies. We compare the retrieved IMG profiles with high-vertical-resolution ozone sonde measurements. Therefore we selected a set of IMG spectra collocated to within 3° of longitude and latitude with a representative distribution of ground-based stations. We demonstrate that thanks to the two to four independent pieces of vertical information contained in the spectroscopic measurements with a maximum sensitivity in the upper troposphere-middle stratosphere, the thermal infrared nadir sounders are able to capture most of the ozone spatial and temporal variations. In particular, the latitudinal variations of the stratospheric ozone maximum are well represented in the retrievals, as are the high ozone concentrations observed in the upper troposphere- lower stratosphere at northern midlatitudes during springtime. Ozone depletion events in the Arctic vortex are also well reproduced. The measurements provide an accurate view of the tropospheric ozone content, except when the latter is very low. A detailed error budget reveals that the major part of the error in the IMG retrieved ozone profile is due to the smoothing of the true profile by the averaging kernel matrix, with additional contributions associated with the measurement noise and the inaccurate knowledge of the temperature profile and of the Instrument Line Shape (ILS). Copyright 2005 by the American Geophysical Union.
BibTeX:
@article{CoheurBarretTurquetyEtAl2005,
  author = {Coheur, P.-F. and Barret, B. and Turquety, S. and Hurtmans, D. and Hadji-Lazaro, J. and Clerbaux, C.},
  title = {Retrieval and characterization of ozone vertical profiles from a thermal infrared nadir sounder},
  journal = {Journal of Geophysical Research Atmospheres},
  year = {2005},
  volume = {110},
  article number = {D24303},
  pages = {1-12},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-31644444574&doi=10.1029%2f2005JD005845&partnerID=40&md5=1c4dfba7489709c4bd884c7370d0260c},
  doi = {10.1029/2005JD005845}
}
Abstract: An emission spectrum of hot water with a temperature of about 3000 K is obtained using an oxy-acetylene torch. This spectrum contains a very large number of transitions. The spectrum, along with previous cooler laboratory emission spectra and an absorption spectrum recorded from a sunspot, is analyzed in the 500-2000 cm -1 region. Use of a calculated variational linelist for water allows significant progress to be made on assigning transitions involving highly excited vibrational and rotational states. In particular emission from rotationally excited states up to J=42 and vibrational levels with up to eight quanta of bending motion are assigned.
BibTeX:
@article{CoheurBernathCarleerEtAl2005,
  author = {Coheur, P.-F. and Bernath, P.F. and Carleer, M. and Colin, R. and Polyansky, O.L. and Zobov, N.F. and Shirin, S.V. and Barber, R.J. and Tennyson, J.},
  title = {A 3000K laboratory emission spectrum of water},
  journal = {Journal of Chemical Physics},
  year = {2005},
  volume = {122},
  article number = {074307},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-22944455179&doi=10.1063%2f1.1847571&partnerID=40&md5=bda43cc96cd48fd61e3fec62e13d1ed1},
  doi = {10.1063/1.1847571}
}
Abstract: Fourier-transform intracavity laser absorption spectroscopy allowed five 12C13CH2Σ+- Σ+ bands, all from the ground state, to be identified in the 0.83 μm range. Their rotational analysis was performed and rotational constants are provided. Three of these bands, with origins at 11616.9684(18), 11737.2356(14), and 11761.0322(23) cm-1, have never been reported before. Their upper states are assigned to V1V2V 3v4l4v5l5 = 1302 020, 130113-1, and 22011 1-1, respectively. © 2004 Elsevier Inc. All rights reserved.
BibTeX:
@article{DepiesseDiLonardoFaytEtAl2005,
  author = {Depiesse, C. and Di Lonardo, G. and Fayt, A. and Fusina, L. and Hurtmans, D. and Robert, S. and Tamassia, F. and Vander Auwera, J. and Baldan, A. and Herman, M.},
  title = {New combination bands in12C13CH2 around 0.83 μm recorded using FT-ICLAS},
  journal = {Journal of Molecular Spectroscopy},
  year = {2005},
  volume = {229},
  pages = {137-139},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-9644278207&doi=10.1016%2fj.jms.2004.08.006&partnerID=40&md5=6793081b86dd0da200a55c3548530c19},
  doi = {10.1016/j.jms.2004.08.006}
}
Abstract: HFC-134a (CF3CH2F) is the most rapidly growing hydrofluorocarbon in terms of atmospheric abundance. It is currently used in a large number of household refrigerators and air-conditioning systems and its concentration in the atmosphere is forecast to increase substantially over the next 50-100 years. Previous estimates of its radiative forcing per unit concentration have differed significantly ∼25%. This paper uses a two-step approach to resolve this discrepancy. In the first step six independent absorption cross section datasets are analysed. We find that, for the integrated cross section in the spectral bands that contribute most to the radiative forcing, the differences between the various datasets are typically smaller than 5% and that the dependence on pressure and temperature is not significant. A "recommended" HFC-134a infrared absorption spectrum was obtained based on the average band intensities of the strongest bands. In the second step, the "recommended" HFC-134a spectrum was used in six different radiative transfer models to calculate the HFC-134a radiative forcing efficiency. The clear-sky instantaneous radiative forcing, using a single global and annual mean profile, differed by 8%, between the 6 models, and the latitudinally-resolved adjusted cloudy sky radiative forcing estimates differed by a similar amount. We calculate that the radiative forcing efficiency of HFC-134a is 0.16 ± 0.02 Wm-2 ppbv-1. © 2004 Elsevier Ltd. All rights reserved.
BibTeX:
@article{ForsterBurkholderClerbauxEtAl2005,
  author = {Forster, P.M.De.F. and Burkholder, J.B. and Clerbaux, C. and Coheur, P.F. and Dutta, M. and Gohar, L.K. and Hurley, M.D. and Myhre, G. and Portmann, R.W. and Shine, K.P. and Wallington, T.J. and Wuebbles, D.},
  title = {Resolution of the uncertainties in the radiative forcing of HFC-134a},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2005},
  volume = {93},
  pages = {447-460},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-13444261008&doi=10.1016%2fj.jqsrt.2004.08.038&partnerID=40&md5=979e96decbb0fb2760884674ac717995},
  doi = {10.1016/j.jqsrt.2004.08.038}
}
Abstract: A set-up combining a high resolution Fourier transform interferometer and a quadrupole mass spectrometer with a supersonic jet expansion produced thanks to a large turbomolecular pumping unit is described. A rotational temperature close to 3 K is demonstrated. Vibration-vibration energy transfer in the expansion affecting the v2 = 1 state in N2O is monitored in the presence of various collision partners. The transfer from the v 2 = 1 state of N2O towards the quasi resonant, lower energy v2 = 1 state of OCS is demonstrated, in particular. © 2005 Elsevier B.V. All rights reserved.
BibTeX:
@article{HermanDidricheRizopoulosEtAl2005,
  author = {Herman, M. and Didriche, K. and Rizopoulos, A. and Hurtmans, D.},
  title = {FT-jet spectroscopy: Vibrational energy transfer in N2O},
  journal = {Chemical Physics Letters},
  year = {2005},
  volume = {414},
  pages = {282-286},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-25844462846&doi=10.1016%2fj.cplett.2005.08.087&partnerID=40&md5=ae7cee2ce9ba76ef9a74b045481c173f},
  doi = {10.1016/j.cplett.2005.08.087}
}
Abstract: The content of the current (2003) version, GEISA/IASI-03, of the computer-accessible spectroscopic database, GEISA/IASI, is described. This "system" or database is comprised of three independent spectroscopic archives, which are (a) a database of individual spectral line parameters on 14 molecules, H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, HNO3, OCS, C2H2, N2, and the related 51 isotopomers and isotopologues, representing 702,550 entries, in the spectral range 599-3001 cm-1, (b) a database of spectral absorption cross-sections (6,572,329 entries related to six molecules, CFC-11, CFC-12, CFC-14, HCFC-22, N2O5, CCl4), and a catalogue of microphysical and optical properties (mainly, the refractive indices) of atmospheric aerosols. The modifications and improvements, which have been implemented since the earlier editions of this database, in terms of content and management, have been explained in detail. GEISA/IASI has been created with the specific purpose of assessing the capability of measurement by the IASI instrument within the designated goals of ISSWG in the frame of the CNES/EUMETSAT European Polar System preparation. All the archived data can be handled through a user-friendly associated management software, which is posted on the ARA/LMD group web site at http://ara.lmd.polyechnique.fr. © 2005 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Jacquinet-HussonScottChedinEtAl2005,
  author = {Jacquinet-Husson, N. and Scott, N.A. and Chédin, A. and Garceran, K. and Armante, R. and Chursin, A.A. and Barbe, A. and Birk, M. and Brown, L.R. and Camy-Peyret, C. and Claveau, C. and Clerbaux, C. and Coheur, P.F. and Dana, V. and Daumont, L. and Debacker-Barilly, M.R. and Flaud, J.M. and Goldman, A. and Hamdouni, A. and Hess, M. and Jacquemart, D. and Köpke, P. and Mandin, J.Y. and Massie, S. and Mikhailenko, S. and Nemtchinov, V. and Nikitin, A. and Newnham, D. and Perrin, A. and Perevalov, V.I. and Régalia-Jarlot, L. and Rublev, A. and Schreier, F. and Schult, I. and Smith, K.M. and Tashkun, S.A. and Teffo, J.L. and Toth, R.A. and Tyuterev, Vl.G. and Vander Auwera, J. and Varanasi, P. and Wagner, G.},
  title = {The 2003 edition of the GEISA/IASI spectroscopic database},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2005},
  volume = {95},
  pages = {429-467},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-21044435328&doi=10.1016%2fj.jqsrt.2004.12.004&partnerID=40&md5=c6938974009cd9c68a43ea2666681495},
  doi = {10.1016/j.jqsrt.2004.12.004}
}
Abstract: We present a complete study on four methane lines for two atmospheric micro-windows (in the ν2 + ν4 absorption band) used for the determination of atmospheric methane concentrations with ground-based Fourier transform spectrometers. Thanks to our tunable diode laser (TDL) spectrometer with active wavenumber control and step-by-step recording mode we have improved the accuracy on intensity, broadening, narrowing, and pressure shift parameters. To make our results directly useable in atmospheric models which usually assume a Voigt line shape, we have parameterised an effective-broadening parameter γVoigt (P) for each line and each gas mixture (CH4-N2 and CH4-O 2). When this parameterisation is used to fit a "true" line profile, the same concentration as with more sophisticated models is retrieved using a consistent set of spectroscopic parameters in both approaches. © 2005 Elsevier Inc. All rights reserved.
BibTeX:
@article{MondelainChelinValentinEtAl2005,
  author = {Mondelain, D. and Chelin, P. and Valentin, A. and Hurtmans, D. and Camy-Peyret, C.},
  title = {Line profile study by diode laser spectroscopy in the 12CH 4 ν2 + ν4 band},
  journal = {Journal of Molecular Spectroscopy},
  year = {2005},
  volume = {233},
  pages = {23-31},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-23844525410&doi=10.1016%2fj.jms.2005.05.012&partnerID=40&md5=24a5fb300ce0d3186af022999bb148fd},
  doi = {10.1016/j.jms.2005.05.012}
}