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28 results on '"Viscardy, Sébastien"'

1. CO2 in the atmosphere of Mars depleted in 13C

Author

Liuzzi, Giuliano, Villanueva, Geronimo L., Aoki, Shohei, Stone, Shane W., Faggi, Sara, Trompet, Loïc, Neary, Lori, Daerden, Frank, Viscardy, Sébastien, Masiello, Guido, Serio, Carmine, Thomas, Ian R., Patel, Manish R., Bellucci, Giancarlo, Lopez-Moreno, Jose-Juan, Ristic, Bojan, and Vandaele, Ann Carine

Published
2024
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2. Methane on Mars and Habitability: Challenges and Responses

Author

Yung, Yuk L, Chen, Pin, Nealson, Kenneth, Atreya, Sushil, Beckett, Patrick, Blank, Jennifer G, Ehlmann, Bethany, Eiler, John, Etiope, Giuseppe, Ferry, James G, Forget, Francois, Gao, Peter, Hu, Renyu, Kleinböhl, Armin, Klusman, Ronald, Lefèvre, Franck, Miller, Charles, Mischna, Michael, Mumma, Michael, Newman, Sally, Oehler, Dorothy, Okumura, Mitchio, Oremland, Ronald, Orphan, Victoria, Popa, Radu, Russell, Michael, Shen, Linhan, Lollar, Barbara Sherwood, Staehle, Robert, Stamenković, Vlada, Stolper, Daniel, Templeton, Alexis, Vandaele, Ann C, Viscardy, Sébastien, Webster, Christopher R, Wennberg, Paul O, Wong, Michael L, and Worden, John

Subjects
Exobiology, Extraterrestrial Environment, Mars, Methane, Spectrum Analysis, Time Factors, CH4, Subsurface redox conditions, Mars instrumentation, Astrobiology 18, xxx-xxx, Astronomical and Space Sciences, Geochemistry, Geology, Astronomy & Astrophysics
Abstract

Recent measurements of methane (CH4) by the Mars Science Laboratory (MSL) now confront us with robust data that demand interpretation. Thus far, the MSL data have revealed a baseline level of CH4 (∼0.4 parts per billion by volume [ppbv]), with seasonal variations, as well as greatly enhanced spikes of CH4 with peak abundances of ∼7 ppbv. What do these CH4 revelations with drastically different abundances and temporal signatures represent in terms of interior geochemical processes, or is martian CH4 a biosignature? Discerning how CH4 generation occurs on Mars may shed light on the potential habitability of Mars. There is no evidence of life on the surface of Mars today, but microbes might reside beneath the surface. In this case, the carbon flux represented by CH4 would serve as a link between a putative subterranean biosphere on Mars and what we can measure above the surface. Alternatively, CH4 records modern geochemical activity. Here we ask the fundamental question: how active is Mars, geochemically and/or biologically? In this article, we examine geological, geochemical, and biogeochemical processes related to our overarching question. The martian atmosphere and surface are an overwhelmingly oxidizing environment, and life requires pairing of electron donors and electron acceptors, that is, redox gradients, as an essential source of energy. Therefore, a fundamental and critical question regarding the possibility of life on Mars is, "Where can we find redox gradients as energy sources for life on Mars?" Hence, regardless of the pathway that generates CH4 on Mars, the presence of CH4, a reduced species in an oxidant-rich environment, suggests the possibility of redox gradients supporting life and habitability on Mars. Recent missions such as ExoMars Trace Gas Orbiter may provide mapping of the global distribution of CH4. To discriminate between abiotic and biotic sources of CH4 on Mars, future studies should use a series of diagnostic geochemical analyses, preferably performed below the ground or at the ground/atmosphere interface, including measurements of CH4 isotopes, methane/ethane ratios, H2 gas concentration, and species such as acetic acid. Advances in the fields of Mars exploration and instrumentation will be driven, augmented, and supported by an improved understanding of atmospheric chemistry and dynamics, deep subsurface biogeochemistry, astrobiology, planetary geology, and geophysics. Future Mars exploration programs will have to expand the integration of complementary areas of expertise to generate synergistic and innovative ideas to realize breakthroughs in advancing our understanding of the potential of life and habitable conditions having existed on Mars. In this spirit, we conducted a set of interdisciplinary workshops. From this series has emerged a vision of technological, theoretical, and methodological innovations to explore the martian subsurface and to enhance spatial tracking of key volatiles, such as CH4.

Published
2018

3. Calibration of the NOMAD-UVIS data

Author

Willame, Yannick, Depiesse, Cédric, Mason, Jonathon P., Thomas, Ian R., Patel, Manish R., Hathi, Brijen, Leese, Mark R., Bolsée, David, Wolff, Michael J., Trompet, Loïc, Vandaele, Ann Carine, Piccialli, Arianna, Aoki, Shohei, Ristic, Bojan, Neefs, Eddy, Beeckman, Bram, Berkenbosch, Sophie, Clairquin, Roland, Mahieux, Arnaud, Pereira, Nuno, Robert, Séverine, Viscardy, Sébastien, Wilquet, Valérie, Daerden, Frank, Lopez-Moreno, José Juan, and Bellucci, Giancarlo

Published
2022
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4. Unexpected increase of the deuterium to hydrogen ratio in the Venus mesosphere.

Author

Mahieux, Arnaud, Viscardy, Sébastien, Yelle, Roger Vincent, Hiroki Karyu, Chamberlain, Sarah, Robert, Séverine, Piccialli, Arianna, Trompet, Loïc, Erwin, Justin Tyler, Ubukata, Soma, Hiromu Nakagawa, Shungo Koyama, Maggiolo, Romain, Pereira, Nuno, Cessateur, Gaël, Willame, Yannick, and Vandaele, Ann Carine

Abstract

This study analyzes H2O and HDO vertical profiles in the Venus mesosphere using Venus Express/Solar Occultation in the InfraRed data. The findings show increasing H2O and HDO volume mixing ratios with altitude, with the D/H ratio rising significantly from 0.025 at ~70 km to 0.24 at ~108 km. This indicates an increase from 162 to 1,519 times the Earth's ratio within 40 km. The study explores two hypotheses for these results: isotopic fractionation from photolysis of H2O over HDO or from phase change processes. The latter, involving condensation and evaporation of sulfuric acid aerosols, as suggested by previous authors [X. Zhang et al., Nat. Geosci. 3, 834-837 (2010)], aligns more closely with the rapid changes observed. Vertical transport computations for H2O, HDO, and aerosols show water vapor downwelling and aerosols upwelling. We propose a mechanism where aerosols form in the lower mesosphere due to temperatures below the water condensation threshold, leading to deuterium-enriched aerosols. These aerosols ascend, evaporate at higher temperatures, and release more HDO than H2O, which are then transported downward. Moreover, this cycle may explain the SO2 increase in the upper mesosphere observed above 80 km. The study highlights two crucial implications. First, altitude variation is critical to determining the Venus deuterium and hydrogen reservoirs. Second, the altitude-dependent increase of the D/H ratio affects H and D escape rates. The photolysis of H2O and HDO at higher altitudes releases more D, influencing long-term D/H evolution. These findings suggest that evolutionary models should incorporate altitude-dependent processes for accurate D/H fractionation predictions. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Comprehensive investigation of Mars methane and organics with ExoMars/NOMAD

Author

Knutsen, Elise W., Villanueva, Geronimo L., Liuzzi, Giuliano, Crismani, Matteo M.J., Mumma, Michael J., Smith, Michael D., Vandaele, Ann Carine, Aoki, Shohei, Thomas, Ian R., Daerden, Frank, Viscardy, Sébastien, Erwin, Justin T., Trompet, Loic, Neary, Lori, Ristic, Bojan, Lopez-Valverde, Miguel Angel, Lopez-Moreno, Jose Juan, Patel, Manish R., Karatekin, Ozgur, and Bellucci, Giancarlo

Published
2021
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6. Viscosity from Newton to Modern Non-equilibrium Statistical Mechanics

Author

Viscardy, Sebastien

Subjects
Condensed Matter - Statistical Mechanics, Physics - History and Philosophy of Physics
Abstract

In the second half of the 19th century, the kinetic theory of gases has probably raised one of the most impassioned debates in the history of science. The so-called reversibility paradox around which intense polemics occurred reveals the apparent incompatibility between the microscopic and macroscopic levels. While classical mechanics describes the motion of bodies such as atoms and molecules by means of time reversible equations, thermodynamics emphasizes the irreversible character of macroscopic phenomena such as viscosity. Aiming at reconciling both levels of description, Boltzmann proposed a probabilistic explanation. Nevertheless, such an interpretation has not totally convinced generations of physicists, so that this question has constantly animated the scientific community since his seminal work. In this context, an important breakthrough in dynamical systems theory has shown that the hypothesis of microscopic chaos played a key role and provided a dynamical interpretation of the emergence of irreversibility. Using viscosity as a leading concept, we sketch the historical development of the concepts related to this fundamental issue up to recent advances. Following the analysis of the Liouville equation introducing the concept of Pollicott-Ruelle resonances, two successful approaches --- the escape-rate formalism and the hydrodynamic-mode method --- establish remarkable relationships between transport processes and chaotic properties of the underlying Hamiltonian dynamics., Comment: 78 pages, 11 figures, submitted to Studies in History and Philosophy of Modern Physics

Published
2006

7. Viscosity and Microscopic Chaos : The Helfand-moment Approach

Author

Viscardy, Sebastien

Subjects
Condensed Matter - Statistical Mechanics
Abstract

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., Comment: PhD Thesis (September 21, 2005) : Center for Nonlinear Phenomena and Complex Systems, Universite Libre de Bruxelles, Belgium (231 pages)

Published
2005

8. On the plausibility of methane detections on Mars in the light of the ExoMars/TGO results

Author

Viscardy, Sébastien, Robert, Séverine, Erwin, Justin, Thomas, Ian R., Daerden, Frank, Neary, Lori, Piccialli, Arianna, Trompet, Loïc, Willame, Yannick, and Vandaele, Ann Carine

Abstract

As a potential biomarker, Martian methane has attracted attention through several reports of its detection over the last 20 years. However, the very existence of this gas has been continuously questioned, in particular, because the observed lifetime should be several orders of magnitude shorter than the 300 years predicted by photochemical models. Although several fast removal processes have been hypothesized to explain the observations, none of them has met a large consensus.It is in this context that the ESA-Roscomos ExoMars Trace Gas Orbiter (TGO) mission started its science operations in April 2018. ACS and NOMAD, two instruments onboard the TGO, have been collecting hundreds of highly sensitive measurements in solar occultation. No methane has been detected so far and an upper limit of 0.02 ppbv has been derived.The implications of this result on the methane problem on Mars will be addressed in this work.This upper limit is a strong constraint on the background level and, in turn, on the potential emission scenarios making the reported methane detections consistent with the TGO results. While several model studies aimed at identifying them, we will here adopt a probabilistic approach to the problem in order to question the plausibility of those detections and estimate the lifetime required to make them plausible from a probabilistic standpoint., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023

10. On the plausibility of methane detections on Mars

Author

Viscardy, Sébastien, primary, Robert, Séverine, additional, Erwin, Justin T., additional, Thomas, Ian R., additional, Daerden, Frank, additional, Neary, Lori, additional, Piccialli, Arianna, additional, Trompet, Loïc, additional, Willame, Yannick, additional, and Vandaele, Ann Carine, additional

Published
2023
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11. Two Martian years at Mars: Observations by NOMAD on ExoMars Trace Gas Orbiter

Author

Vandaele, Ann Carine, primary, Daerden, Frank, additional, Thomas, Ian R., additional, Depiesse, Cédric, additional, Erwin, Justin, additional, Flimon, Zachary, additional, Neary, Lori, additional, Piccialli, Arianna, additional, Ristic, Bojan, additional, Trompet, Loïc, additional, Viscardy, Sébastien, additional, Willame, Yannick, additional, Aoki, Shohei, additional, Gérard, Jean-Claude, additional, Villanueva, Geronimo, additional, Mason, Jon, additional, Patel, Manish, additional, Bellucci, Giancarlo, additional, Lopez-Valverde, Miguel, additional, and Lopez-Moreno, Jose Juan, additional

Published
2022
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12. Ozone in the Martian atmosphere observed by TGO/NOMAD-UVIS solar occultations

Author

Piccialli, Arianna, primary, Vandaele, Ann Carine, additional, Willame, Yannick, additional, Määttänen, Anni, additional, Trompet, Loïc, additional, Erwin, Justin, additional, Daerden, Frank, additional, Neary, Lori, additional, Aoki, Shohei, additional, Viscardy, Sébastien, additional, Thomas, Ian, additional, Depiesse, Cedric, additional, Ristic, Bojan, additional, Mason, Jon, additional, Patel, Manish, additional, Wolff, Michael, additional, Khayat, Alain, additional, Bellucci, Giancarlo, additional, and Lopez-Moreno, Jose Juan, additional

Published
2022
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13. Publisher Correction: No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations

Author

Korablev, Oleg, Vandaele, Ann Carine, Montmessin, Franck, Fedorova, Anna A., Trokhimovskiy, Alexander, Forget, François, Lefèvre, Franck, Daerden, Frank, Thomas, Ian R., Trompet, Loïc, Erwin, Justin T., Aoki, Shohei, Robert, Séverine, 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., and The ACS and NOMAD Science Teams

Published
2019
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14. Publisher Correction: Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter

Author

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., Young, Roland, Svedhem, Håkan, Vago, Jorge L., Rodionov, Daniel, NOMAD Science Team, and ACS Science Team

Published
2019
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15. The Martian environment observed by NOMAD on ExoMars Trace Gas Orbiter

Author

Vandaele, Ann Carine, primary, Daerden, Frank, additional, Thomas, Ian R., additional, Aoki, Shohei, additional, Depiesse, Cédric, additional, Erwin, Justin, additional, Neary, Lori, additional, Piccialli, Arianna, additional, Ristic, Bojan, additional, Robert, Séverine, additional, Trompet, Loïc, additional, Viscardy, Sébastien, additional, Willame, Yannick, additional, Gérard, Jean-Claude, additional, Villanueva, Geronimo, additional, Mason, Jon, additional, Patel, Manish, additional, Bellucci, Giancarlo, additional, Lopez-Valverde, Miguel, additional, and Lopez-Moreno, Jose-Juan, additional

Published
2021
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16. Water Vapor Vertical Profiles on Mars in Dust Storms Observed by TGO/NOMAD

Author

Aoki, Shohei, Vandaele, Ann Carine, Daerden, Frank, Villanueva, Geronimo L., Liuzzi, Giuliano, Thomas, Ian R., Erwin, Justin T., Trompet, Loïc, Robert, S., Neary, Lori, Viscardy, Sébastien, Clancy, Todd, Smith, Michael D., López-Valverde, Miguel, Hill, B., Ristic, Bojan, Patel, Manish R., Bellucci, Giancarlo, López-Moreno, Jose-Juan, Alonso-Rodrigo, G., Altieri, F., Bauduin, Sophie, and Bolsée, D.

Subjects
Sciences de la terre et du cosmos, Aéronomie, Télédétection, Système solaire, Sciences exactes et naturelles
Abstract

0, info:eu-repo/semantics/published

Published
2019

17. NOMAD on ExoMars Trace Gas Orbiter: One Martian year of observations

Author

Vandaele, Ann Carine, primary, Daerden, Frank, additional, Thomas, Ian R., additional, Aoki, Shohei, additional, Depiesse, Cédric, additional, Erwin, Justin, additional, Neary, Lori, additional, Piccialli, Arianna, additional, Ristic, Bojan, additional, Robert, Séverine, additional, Trompet, Loïc, additional, Viscardy, Sébastien, additional, Willame, Yannick, additional, Mason, Jon, additional, Patel, Manish, additional, Bellucci, Giancarlo, additional, and Lopez-Moreno, Jose-Juan, additional

Published
2020
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19. Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter

Author

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

Subjects
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.

Published
2019

20. No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations

Author

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)

Subjects
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).

Published
2019

21. Retrievals of Ozone at the Terminator of Mars from Spicam/mex Solar Occultations

Author

Piccialli, Arianna, Vandaele, Ann Carine, Robert, Séverine, Daerden, F., Viscardy, Sébastien, Trompet, Loic, Neary, Lori, Aoki, Shohei, Willame, Yannick, Wilquet, Valérie, Lefèvre, Franck, Määttänen, Anni, Montmessin, Franck, Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Fonds National de la Recherche Scientifique [Bruxelles] (FNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (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), Cardon, Catherine, and 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)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

22. NOMAD, an integrated suite of three spectrometers for the ExoMars trace gas mission: Technical description, science objectivs and expected performance

Author

Vandaele, Ann Carine, Lopez-Moreno, J.-J., Patel, M.R., Bellucci, G., Daerden, F., Ristic, B., Robert, Séverine, Thomas, I.R., Wilquet, Valérie, Allen, M., Alonso-Rodrigo, G., Altieri, F., Aoki, S, Bolsée, D., Clancy, T., Cloutis, E., Depiesse, Cédric, Drummond, Rachel, Fedorova, A., Formisano, V., Funke, Bernd, Gonzalez-Galindo, F., Geminale, A., Gérard, J.-C., Giuranna, M., Hetey, L., Ignatiev, N., Kaminski, J., Karatekin, Ozgur, Kasaba, Y., Leese, M., Lefèvre, F., Lewis, S. R., Lopez-Puertas, Manuel, Lopez-Valverde, M.A., Mahieux, Arnaud, Mason, James, McConnell, John, Mumma, M., Neary, L., Neefs, Eddy, Renotte, E., Gómez-Rodriguez, Julio, Sindoni, G., Smith, M., Stiepen, A., Trokhimovsky, A., Vander Auwera, Jean, Villanueva, G., Viscardy, Sébastien, Whiteway, J.A., Willame, Yannick, Wolff, M., and NOMAD, Team

Subjects
Spectroscopie [électromagnétisme, optique, acoustique], Chimie, Physique atomique et moléculaire
Abstract

info:eu-repo/semantics/published

Published
2018

23. A test case: new retrievals of ozone at the terminator on Mars

Author

Piccialli, Arianna, Vandaele, Ann Carine, Robert, Séverine, Daerden, Frank, Viscardy, Sébastien, Neary, Lori, Aoki, Shohei, Wilquet, Valérie, Lefèvre, Franck, Määttänen, Anni, Montmessin, Franck, Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Fonds National de la Recherche Scientifique [Bruxelles] (FNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; ASIMUT, the BIRA-IASB radiative transfer code, was modified in order to take into account the changes in the atmospheric composition and structure across the martian day/night terminator.Here, we will discuss the impact of this implementation on the retrievals of ozone profiles derived from SPICAM solar occultations in the ultraviolet.

Published
2017

24. Viscosity and Microscopic Chaos: The Helfand-moment Approach (Viscosité et Chaos Microscopique: Approche par le Moment de Helfand)

Author

Viscardy, Sébastien, Nicolis, Grégoire, Turner, John W., Mareschal, Michel, Dorfman, J. Robert, Buess-Herman, Claudine, and Gaspard, Pierre

Subjects
histoire des sciences / history of science, mécanique statistique de non-équilib, dynamique moléculaire / molecular dynamics, processus de transport / transport processes, théorie des systèmes dynamiques / dy, viscosité / viscosity, chaos microscopique / microscopic chaos
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/published

Published
2005

25. Viscosité et chaos mircroscopique: approche par le moment de Helfand

Author

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

26. Ground-based infrared mapping of H2O2 on Mars near opposition.

Author

Encrenaz, Therese, Geathouse, Thomas, Aoki, Shohei, Daerden, Frank, Giuranna, Marco, Lefèvre, Franck, Montmessin, Franck, Forget, François, Fouchet, Thierry, Bézard, Bruno, Atreya, Sushil, DeWitt, Curtis, Richter, Matthew, Neary, Lori, and Viscardy, Sébastien

Published
2019

27. Martian dust storm impact on atmospheric H 2 O and D/H observed by ExoMars Trace Gas Orbiter.

Author

Vandaele AC, Korablev O, Daerden F, Aoki S, Thomas IR, Altieri F, López-Valverde M, Villanueva G, Liuzzi G, Smith MD, Erwin JT, Trompet L, Fedorova AA, Montmessin F, Trokhimovskiy A, Belyaev DA, Ignatiev NI, Luginin M, Olsen KS, Baggio L, Alday J, Bertaux JL, Betsis D, Bolsée D, Clancy RT, Cloutis E, Depiesse C, Funke B, Garcia-Comas M, Gérard JC, Giuranna M, Gonzalez-Galindo F, Grigoriev AV, Ivanov YS, Kaminski J, Karatekin O, Lefèvre F, Lewis S, López-Puertas M, Mahieux A, Maslov I, Mason J, Mumma MJ, Neary L, Neefs E, Patrakeev A, Patsaev D, Ristic B, Robert S, Schmidt F, Shakun A, Teanby NA, Viscardy S, Willame Y, Whiteway J, Wilquet V, Wolff MJ, Bellucci G, Patel MR, López-Moreno JJ, Forget F, Wilson CF, Svedhem H, Vago JL, and Rodionov D

Abstract

Global dust storms on Mars are rare 1,2 but can affect the Martian atmosphere for several months. They can cause changes in atmospheric dynamics and inflation of the atmosphere 3 , primarily owing to solar heating of the dust 3 . In turn, changes in atmospheric dynamics can affect the distribution of atmospheric water vapour, with potential implications for the atmospheric photochemistry and climate on Mars 4 . 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 latitudes 5,6 , as well as a decrease in the water column at low latitudes 7,8 . 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/H 2 O 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 H 2 O 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 crystals 3 . The observed changes in H 2 O 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.

Published
2019
Full Text
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28. No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations.

Author

Korablev O, Vandaele AC, Montmessin F, Fedorova AA, Trokhimovskiy A, Forget F, Lefèvre F, Daerden F, Thomas IR, Trompet L, Erwin JT, Aoki S, Robert S, Neary L, Viscardy S, Grigoriev AV, Ignatiev NI, Shakun A, Patrakeev A, Belyaev DA, Bertaux JL, Olsen KS, Baggio L, Alday J, Ivanov YS, Ristic B, Mason J, Willame Y, Depiesse C, Hetey L, Berkenbosch S, Clairquin R, Queirolo C, Beeckman B, Neefs E, Patel MR, Bellucci G, López-Moreno JJ, Wilson CF, Etiope G, Zelenyi L, Svedhem H, and Vago JL

Abstract

The detection of methane on Mars has been interpreted as indicating that geochemical or biotic activities could persist on Mars today 1 . A number of different measurements of methane show evidence of transient, locally elevated methane concentrations and seasonal variations in background methane concentrations 2-5 . These measurements, however, are difficult to reconcile with our current understanding of the chemistry and physics of the Martian atmosphere 6,7 , which-given methane's lifetime of several centuries-predicts an even, well mixed distribution of methane 1,6,8 . 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 detections 2,4 . We suggest that reconciliation between the present findings and the background methane concentrations found in the Gale crater 4 would require an unknown process that can rapidly remove or sequester methane from the lower atmosphere before it spreads globally.

Published
2019
Full Text
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