SPICAM on Mars Express: a 10 year in-depth survey of the Martian atmosphere

Franck Montmessin (1) , Oleg Korablev (2) , Franck Lefèvre (1) , Jean-Loup Bertaux (3) , Anna Fedorova (2) , Alexander Trokhimovskiy (4, 2) , Gaetan Lacombe (5) , Aurélie Reberac (5) , Nicolas Chapron (5) , Luca Maltagliati (6) , Svetlana Guslyakova (4, 2) , Jean-Yves Chaufray (1) , Jean-Claude Gérard (7) , Yannick Willame (8) , Anni Määttänen (1) , Arnaud Stiepen (9) , François Forget (10) , Olivier Witasse (11) , Didier Fussen (8) , Nina Mateshvili (8) , Ann-Carine Vandaele (8) , Emmanuel Marcq (1) , Bill R. Sandel (12) , Brigitte Gondet (13) , Nicholas Schneider (9) , Michael Chaffin (9)

1 PLANETO - LATMOS
2 IKI - Space Research Institute of the Russian Academy of Sciences
3 STRATO - LATMOS
4 MIPT - Moscow Institute of Physics and Technology [Moscow]
5 LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
6 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
7 LPAP - Laboratoire de Physique Atmosphérique et Planétaire
8 BIRA-IASB - Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
9 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
10 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
11 ESTEC - European Space Research and Technology Centre
12 LPL - Lunar and Planetary Laboratory [Tucson]
13 IAS - Institut d'astrophysique spatiale

The SPICAM experiment onboard Mars Express has accumulated over the last decade a wealth of observations that has permitted a detailed characterization of the atmospheric composition and activity from the near-surface to above the exosphere. SPICAM is dual ultraviolet (110 to 320 nm)-infrared (1 to 1.7 µm) spectrometer specifically designed to retrieve the major and minor species abundances of the Martian atmosphere [1]. SPICAM has the distinct capability of observing with a variety of geometrical configurations; monitoring the column-integrated abundances of ozone, water vapor as well as aerosols in a nadir-looking mode, characterizing their vertical distribution in either stellar or solar occultation modes so as to constrain their presence above typically 10 km up to 140 km of altitude (for CO 2) [2,3,4]. In a dedicated limb staring mode, SPICAM can infer the density of hydrogen atoms from 200 up to 10 000 km of altitude while using the resonantly scattered solar photons at the Lyman-alpha emission line of Hydrogen [5,6].Since the beginning of its operations at Mars, SPICAM has performed several thousands of stellar and solar occultations and has provided a multi-annual tracking in nadir mode. Here, we present a synthesis of the observations collected to date in order to assemble a single, coherent picture of the Martian atmosphere specifically adressing the issue of water decomposition into its lighter component (hydrogen) that can escape to space. In doing so, we propose a different angle for the long-term evolution of water and hydrogen on Mars.

Domains: Earth and Planetary Astrophysics [astro-ph.EP]

Franck Montmessin, Oleg Korablev, Franck Lefèvre, Jean-Loup Bertaux, Anna Fedorova, et al.. SPICAM on Mars Express: a 10 year in-depth survey of the Martian atmosphere . EGU General Assembly 2015, Apr 2015, Vienna, Austria. pp.EGU2015-6376. ⟨insu-01144512⟩