4 results on '"Viscardy, Sébastien"'
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2. Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter
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Vandaele, Ann Carine, Korablev, Oleg, Daerden, Frank, Aoki, Shohei, Thomas, Ian R., ALTIERI, FRANCESCA, López-Valverde, Miguel, Villanueva, Geronimo, Liuzzi, Giuliano, Smith, Michael D., Erwin, Justin T., Trompet, Loïc, Fedorova, Anna A., Montmessin, Franck, Trokhimovskiy, Alexander, Belyaev, Denis A., Ignatiev, Nikolay I., Luginin, Mikhail, Olsen, Kevin S., Baggio, Lucio, Alday, Juan, Bertaux, Jean-Loup, Betsis, Daria, Bolsée, David, Clancy, R. Todd, CLOUTIS, EDWARD, Depiesse, Cédric, Funke, Bernd, Garcia-Comas, Maia, Gérard, Jean-Claude, GIURANNA, MARCO, Gonzalez-Galindo, Francisco, Grigoriev, Alexey V., Ivanov, Yuriy S., Kaminski, Jacek, Karatekin, Ozgur, Lefèvre, Franck, Lewis, Stephen, López-Puertas, Manuel, Mahieux, Arnaud, Maslov, Igor, Mason, Jon, Mumma, Michael J., Neary, Lori, Neefs, Eddy, Patrakeev, Andrey, Patsaev, Dmitry, Ristic, Bojan, Robert, Séverine, Schmidt, Frédéric, Shakun, Alexey, Teanby, Nicholas A., Viscardy, Sébastien, Willame, Yannick, Whiteway, James, Wilquet, Valérie, Wolff, Michael J., BELLUCCI, Giancarlo, Patel, Manish R., López-Moreno, Jose-Juan, Forget, François, Wilson, Colin F., Svedhem, Håkan, Vago, Jorge L., Rodionov, Daniel, NOMAD Science Team, Alonso-Rodrigo, Gustavo, Bauduin, Sophie, Carrozzo, Giacomo, Crismani, Matteo, da Pieve, Fabiana, D'AVERSA, EMILIANO, Etiope, Giuseppe, Fussen, Didier, Geminale, Anna, Gkouvelis, Leo, Holmes, James, Hubert, Benoît, Ignatiev, Nicolay I., Kasaba, Yasumasa, Kass, David, Kleinböhl, Armin, LANCIANO, ORIETTA, Nakagawa, Hiromu, Novak, Robert E., Oliva, Fabrizio, Piccialli, Arianna, Renotte, Etienne, Ritter, Birgit, Schneider, Nick, SINDONI, Giuseppe, Thiemann, Ed, Vander Auwera, Jean, Wilquet, Valerie, WOLKENBERG, PAULINA MARIA, Yelle, Roger, ACS Science Team, Anufreychik, Konstantin, Arnold, Gabriele, Duxbury, Natalia, Fouchet, Thierry, GRASSI, Davide, Guerlet, Sandrine, Hartogh, Paul, Khatuntsev, Igor, Kokonkov, Nikita, Krasnopolsky, Vladimir, Kuzmin, Ruslan, Lacombe, Gaétan, Lellouch, Emmanuel, Määttänen, Anni, Marcq, Emmanuel, Martin-Torres, Javier, Medvedev, Alexander, Millour, Ehouarn, Moshkin, Boris, Quantin-Nataf, Cathy, Rodin, Alexander, Shematovich, Valery, Thomas, Nicolas, Trokhimovsky, Alexander, Vazquez, Luis, Vincendon, Matthieu, Young, Roland, Zasova, Ludmila, Zelenyi, Lev, Zorzano, Maria Paz, Parejo, J, Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), Main Astronomical Observatory of NAS of Ukraine (MAO), National Academy of Sciences of Ukraine (NASU), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Instituto Universitario de Microgravedad 'Ignacio Da Riva' (IDR), Universidad Politécnica de Madrid (UPM), Spectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique, Université libre de Bruxelles (ULB), Space Science Institute [Boulder] (SSI), Department of Geography [Winnipeg], University of Winnipeg, NASA Goddard Space Flight Center (GSFC), Laboratoire de Physique Atmosphérique et Planétaire (LPAP), Université de Liège, School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Institute of Geophysics [Warsaw], Polska Akademia Nauk = Polish Academy of Sciences (PAN), Royal Observatory of Belgium [Brussels] (ROB), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Agenzia Spaziale Italiana (ASI), Graduate School of Information Sciences [Sendai], Tohoku University [Sendai], Advanced Mechanical and Optical Systems SA (AMOS), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], School of Earth Sciences [Bristol], University of Bristol [Bristol], Centre for Research in Earth and Space Science [Toronto] (CRESS), York University [Toronto], Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Department of Physics [Oxford], University of Oxford [Oxford], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Lomonosov Moscow State University (MSU), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institute for Astrophysics and Computational Sciences [Washington], Catholic University of America, Department of Computer Science, Electrical and Space Engineering [Luleå], Luleå University of Technology (LUT), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Moscow Institute of Physics and Technology [Moscow] (MIPT), Institute of Astronomy of the Russian Academy of Sciences (INASAN), University of Bern, Universidad Complutense de Madrid = Complutense University of Madrid [Madrid] (UCM), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Université Libre de Bruxelles [Bruxelles] (ULB), The Open University [Milton Keynes] (OU), Polska Akademia Nauk (PAN), Royal Observatory of Belgium [Brussels], IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidad Complutense de Madrid [Madrid] (UCM), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Agence Spatiale Européenne = European Space Agency (ESA), University of Oxford, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Ministerio de Ciencia e Innovación (España), European Space Agency, Belgian Science Policy Office, European Commission, UK Space Agency, Agenzia Spaziale Italiana, Ministerio de Ciencia, Innovación y Universidades (España), Fonds de la Recherche Scientifique (Fédération Wallonie-Bruxelles), Roscosmos, Centre National de la Recherche Scientifique (France), and Russian Government
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Martian ,Ice cloud ,Multidisciplinary ,010504 meteorology & atmospheric sciences ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,Storm ,Atmosphere of Mars ,Atmospheric sciences ,01 natural sciences ,Trace gas ,chemistry.chemical_compound ,chemistry ,13. Climate action ,Dust storm ,0103 physical sciences ,Environmental science ,Semiheavy water ,010303 astronomy & astrophysics ,Water vapor ,0105 earth and related environmental sciences ,Sciences exactes et naturelles - Abstract
A publisher correction to this article was published on 17 April 2019, 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., This project acknowledges funding by the Belgian Science Policy Office (BELSPO), with financial and contractual coordination by the ESA Prodex Office (PEA 4000103401, 4000121493); by the Spanish MICINN through its Plan Nacional and by European funds under grants ESP2015-65064-C2-1-P and ESP2017-87143-R (MINECO/FEDER); by the UK Space Agency through grants ST/R005761/1, ST/P001262/1, ST/R001405/1, ST/S00145X/1, ST/R001367/1, ST/P001572/1 and ST/R001502/1; and the Italian Space Agency through grant 2018-2-HH.0. The IAA/CSIC team acknowledges financial support from the State Agency for Research of the Spanish MCIU through the 'Center of Excellence Severo Ochoa' award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). This work was supported by the Belgian Fonds de la Recherche Scientifique - FNRS under grant number 30442502 (ET_HOME). The ACS experiment is led by IKI, Space Research Institute in Moscow, assisted by LATMOS in France. The project acknowledges funding by Roscosmos and CNES. The science operations of ACS are funded by Roscosmos and ESA. IKI affiliates acknowledge funding under grant number 14.W03.31.0017 and contract number 0120.0 602993 (0028-2014-0004) of the Russian government.
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- 2019
3. No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations
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Korablev, Oleg, Avandaele, Ann Carine, Montmessin, Franck, Fedorova, Anna A., Trokhimovskiy, Alexander, Forget, François, Lefèvre, Franck, Daerden, Frank, Thomas, Ian R., Trompet, Loïc, Erwin, Justin T., Kasaba, Yasumasa, Kass, David, Khatuntsev, Igor, Kleinböhl, Armin, Kokonkov, Nikita, Krasnopolsky, Vladimir, Kuzmin, Ruslan, Lacombe, Gaétan, LANCIANO, ORIETTA, Lellouch, Emmanuel, Oliva, Fabrizio, Lewis, Stephen, Luginin, Mikhail, Liuzzi, Giuliano, López-Puertas, Manuel, López-Valverde, Miguel, Määttänen, Anni, Mahieux, Arnaud, Marcq, Emmanuel, Martin-Torres, Javier, Maslov, Igor, Patsaev, Dmitry, Medvedev, Alexander, Millour, Ehouarn, Moshkin, Boris, Mumma, Michael J., Nakagawa, Hiromu, Novak, Robert E., Piccialli, Arianna, Quantin-Nataf, Cathy, Renotte, Etienne, Ritter, Birgit, Rodin, Alexander, Schmidt, Frédéric, Schneider, Nick, Shematovich, Valery, Aoki, Shohei, Smith, Michael D., Teanby, Nicholas A., Thiemann, Ed, Thomas, Nicolas, Vander Auwera, Jean, Vazquez, Luis, Villanueva, Geronimo, Vincendon, Matthieu, Whiteway, James, Wilquet, Valérie, Robert, Séverine, Wolff, Michael J., WOLKENBERG, PAULINA MARIA, Yelle, Roger, Young, Roland, Zasova, Ludmila, Zorzano, Maria Paz, Neary, Lori, Viscardy, Sébastien, Grigoriev, Alexey V., Ignatiev, Nikolay I., Shakun, Alexey, Patrakeev, Andrey, Belyaev, Denis A., Bertaux, Jean-Loup, Olsen, Kevin S., Baggio, Lucio, Alday, Juan, Ivanov, Yuriy S., Ristic, Bojan, Mason, Jon, Willame, Yannick, Depiesse, Cédric, Hetey, Laszlo, Berkenbosch, Sophie, Clairquin, Roland, Queirolo, Claudio, Beeckman, Bram, Neefs, Eddy, Patel, Manish R., BELLUCCI, Giancarlo, López-Moreno, Jose-Juan, Wilson, Colin F., Etiope, Giuseppe, Zelenyi, Lev, Svedhem, Håkan, Vago, Jorge L., ACS Science Team, NOMAD Science Team, Alonso-Rodrigo, Gustavo, ALTIERI, FRANCESCA, Anufreychik, Konstantin, Arnold, Gabriele, Bauduin, Sophie, Bolsée, David, CARROZZO, FILIPPO GIACOMO, Clancy, R. Todd, CLOUTIS, EDWARD, Crismani, Matteo, da Pieve, Fabiana, D'AVERSA, EMILIANO, Duxbury, Natalia, Encrenaz, Therese, Fouchet, Thierry, Funke, Bernd, Fussen, Didier, Garcia-Comas, Maia, Gérard, Jean-Claude, GIURANNA, MARCO, Gkouvelis, Leo, Gonzalez-Galindo, Francisco, GRASSI, Davide, Guerlet, Sandrine, Hartogh, Paul, Holmes, James, Hubert, Benoît, Kaminski, Jacek, Karatekin, Ozgur, Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Physics [Oxford], University of Oxford [Oxford], Main Astronomical Observatory of NAS of Ukraine (MAO), National Academy of Sciences of Ukraine (NASU), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Roma (INGV), Istituto Nazionale di Geofisica e Vulcanologia, Faculty of Environmental Science and Engineering [Cluj-Napoca], Babes-Bolyai University [Cluj-Napoca] (UBB), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Instituto Universitario de Microgravedad 'Ignacio Da Riva' (IDR), Universidad Politécnica de Madrid (UPM), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Spectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique, Université libre de Bruxelles (ULB), Space Science Institute [Boulder] (SSI), Department of Geography [Winnipeg], University of Winnipeg, NASA Goddard Space Flight Center (GSFC), Lomonosov Moscow State University (MSU), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Atmosphérique et Planétaire (LPAP), Université de Liège, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institute of Geophysics [Warsaw], Polska Akademia Nauk = Polish Academy of Sciences (PAN), Royal Observatory of Belgium [Brussels] (ROB), Graduate School of Information Sciences [Sendai], Tohoku University [Sendai], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institute for Astrophysics and Computational Sciences [Washington], Catholic University of America, Agenzia Spaziale Italiana (ASI), Department of Computer Science, Electrical and Space Engineering [Luleå], Luleå University of Technology (LUT), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Advanced Mechanical and Optical Systems SA (AMOS), Moscow Institute of Physics and Technology [Moscow] (MIPT), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Institute of Astronomy of the Russian Academy of Sciences (INASAN), School of Earth Sciences [Bristol], University of Bristol [Bristol], University of Bern, Universidad Complutense de Madrid = Complutense University of Madrid [Madrid] (UCM), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre for Research in Earth and Space Science [Toronto] (CRESS), York University [Toronto], Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Belgian Science Policy Office, Ministerio de Ciencia e Innovación (España), European Commission, UK Space Agency, Centre National de la Recherche Scientifique (France), Fonds de la Recherche Scientifique (Fédération Wallonie-Bruxelles), Roscosmos, Russian Government, Agenzia Spaziale Italiana, European Space Agency, IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), The Open University [Milton Keynes] (OU), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Université Libre de Bruxelles [Bruxelles] (ULB), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Polska Akademia Nauk (PAN), Royal Observatory of Belgium [Brussels], Universidad Complutense de Madrid [Madrid] (UCM), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), University of Oxford, Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)
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Martian ,Multidisciplinary ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,010504 meteorology & atmospheric sciences ,Chemistry ,Atmosphere of Mars ,Mars Exploration Program ,01 natural sciences ,7. Clean energy ,Methane ,Trace gas ,law.invention ,Astrobiology ,Atmosphere ,Orbiter ,chemistry.chemical_compound ,13. Climate action ,law ,Atmospheric chemistry ,0103 physical sciences ,010303 astronomy & astrophysics ,Sciences exactes et naturelles ,0105 earth and related environmental sciences - Abstract
A publisher correction to this article was published on 17 April 2019, 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., ExoMars is the space mission of ESA and Roscosmos. The ACS experiment is led by IKI, the Space Research Institute in Moscow, assisted by LATMOS in France. The project acknowledges funding by Roscosmos and CNES. The science operations of ACS are funded by Roscosmos and ESA. IKI affiliates acknowledge funding under grant number 14.W03.31.0017 and contract number 0120.0 602993 (0028-2014-0004) of the Russian government. The NOMAD experiment is led by the Royal Belgian Institute for Space Aeronomy (BIRA-IASB), assisted by co-PI teams from Spain (IAA-CSIC), Italy (INAF-IAPS), and the UK (Open University). This project acknowledges funding by the Belgian Science Policy Office (BELSPO), with the financial and contractual coordination of the ESA Prodex Office (PEA 4000103401 and PEA 4000121493), by Spanish MICINN through its Plan Nacional and by European funds under grants ESP2015-65064-C2-1-P and ESP2017-87143-R (MINECO/FEDER), as well as by the UK Space Agency through grants ST/R005761/1, ST/P001262/1, ST/R001405/1, ST/S00145X/1, ST/R001367/1, ST/P001572/1 and ST/R001502/1, and the Italian Space Agency through grant 2018-2-HH.0. This work was supported by the Belgian Fonds de la Recherche Scientifique-FNRS under grant number 30442502 (ET_HOME).
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- 2019
4. Viscosité et chaos mircroscopique: approche par le moment de Helfand
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Viscardy, Sébastien, Gaspard, Pierre, Buess Herman, Claudine, Nicolis, Grégoire, Turner, John, Mareschal, Michel, and Dorfman, J. Robert
- Subjects
Théorie des systèmes ,Viscosity ,dynamique moléculaire / molecular dynamics ,Transport, Théorie du ,chaos microscopique / microscopic chaos ,Molecular dynamics ,histoire des sciences / history of science ,Transport theory ,Viscosité ,mécanique statistique de non-équilib ,Dynamique moléculaire ,processus de transport / transport processes ,Chimie ,théorie des systèmes dynamiques / dy ,viscosité / viscosity ,System theory ,Sciences exactes et naturelles - Abstract
Depuis les premiers développements de la physique statistique réalisés au 19ème siècle, nombreux ont été les travaux dédiés à la relation entre les processus macroscopiques em>irréversibles(tels que les phénomènes de transport) et les propriétés de la dynamique réversible des atomes et des molécules. Depuis deux décennies, l'hypothèse du chaos microscopique nous en apporte une plus grande compréhension. Dans cette thèse, nous nous intéressons plus particulièrement aux propriétés de viscosité. Dans ce travail, nous considérons des systèmes périodiques de particules en interaction. Nous proposons une nouvelle méthode de calcul de la viscosité valable pour tous systèmes périodiques, quel que soit le potentiel d'interaction considéré. Cette méthode est basée sur la formule dérivée par Helfand exprimant la viscosité en fonction de la variance du moment de Helfand croissant linéairement dans le temps.Dans les années nonante, il a été démontré qu'un système composé de seulement deux particules présente déjà de la viscosité. Les deux disques durs interagissent en collisions élastiques dans un domaine carré ou hexagonal avec des conditions aux bords périodiques. Nous appliquons notre méthode de calcul des propriétés de viscosité dans les deux réseaux. Nous donnons également une explication qualitative des résultats obtenus. L'étude de la relation entre les propriétés de viscosité et les grandeurs du chaos microscopique représente l'une des principales tâches de cette thèse. Dans ce contexte, le formalisme du taux d'échappement joue un rôle majeur. Ce formalisme établit une relation directe entre cette grandeur et la viscosité. Nous étudions numériquement cette relation et la comparaison avec les résultats obtenus par notre méthode sont excellents. D'autre part, le formalisme du taux d'échappement suppose l'existence d'un répulseur fractal. Après avoir mis en évidence son existence, nous appliquons le formalisme proposant une formule exprimant la viscosité en termes de l'exposant de Lyapunov du système (mesurant le caractère chaotique de la dynamique)et de la dimension fractale du répulseur. L'étude numérique de cette relation dans le modèle à deux disques durs est réalisée avec succès et sont en excellent accord avec les relations obtenus précédemment. Enfin, nous nous penchons sur les systèmes composés de N disques durs ou sphères dures. Après une étude de l'équation d'état et des propriétés chaotiques, nous avons exploré les propriétés de viscosité dans ces systèmes. Les données numériques obtenues sont en très bon accord avec les prévisions théoriques d'Enskog. D'autre part, nous avons utilisé notre méthode de calcul de la viscosité dans des systèmes de Lennard-Jones. De plus, nous avons proposé une méthode analogue pour le calcul numérique de la conduction thermique. Nos résultats sont en très bon accord avec ceux obtenus par la méthode de Green-Kubo.In this thesis, we first devote a section on the history of the concept of irreversibility; of the hydrodynamics, branch of physics in which the viscosity appears; of the kinetic theory of gases establishing relationships between the microscopic dynamics and macroscopic processes like viscosity; and, finally, the interest brought in statistical mechanics of irreversible processes by the theory of chaos, more precisely, the microscopic chaos. We propose a method based on the Helfand moment in order to calculate the viscosity properties in systems of particles with periodic boundary conditions. We apply this method to the simplest system in which viscosity already exists: the two-hard-disk model. The escape-rate formalism, establishing a direct relation between chaotic quantities of the microscopic dynamics (e.g. Lyapunov exponents, fractal dimensions, etc.), is applied in this system. The results are in excellent agreement with those obtained by our Helfand-moment method. We extend the calculation of the viscosity properties to systems with more than two hard balls. Finally, we compute viscosity as well as thermal conductivity thanks to our own method also based on the Helfand moment., Doctorat en sciences, Spécialisation physique, info:eu-repo/semantics/nonPublished
- Published
- 2005
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