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Sublimation of the Martian CO2 Seasonal South Polar Cap |
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| Authors: | Frédéric Schmidt Bernard Schmitt Francois Forget Patrick Martin Jean-Pierre Bibring the OMEGA Team |
| Institution: | a ESAC, PO Box 78, E-28691 Villanueva de la Canada, Madrid, Spain b IDES, Université Paris-Sud 11, CNRS/INSU, Bâtiment 509, Université Paris-Sud, 91405 Orsay, France c Laboratoire de Planétologie de Grenoble, Université de Grenoble, CNRS/INSU, BP 53, 38041 Grenoble Cedex 9, France d Laboratoire de Météorologie Dynamique, Institut Pierre Simon Laplace, Université Paris VI, CNRS/INSU, BP99, 75252 Paris Cedex 05, France e Institute of Astronomy, National Central University, 10F, No. 439, Dunhua Road, Beitun District, Taichung City 406, Taiwan f Institut d’Astrophysique Spatiale, Université Paris-Sud 11, CNRS/INSU, Batiment 121, 91405 Orsay cedex, France |
| Abstract: | The polar condensation/sublimation of CO2, that involve about one fourth of the atmosphere mass, is the major Martian climatic cycle. Early observations in visible and thermal infrared have shown that the sublimation of the Seasonal South Polar Cap (SSPC) is not symmetric around the geographic South Pole.Here we use observations by OMEGA/Mars Express in the near-infrared to detect unambiguously the presence of CO2 at the surface, and to estimate albedo. Second, we estimate the sublimation of CO2 released in the atmosphere and show that there is a two-step process. From Ls=180° to 220°, the sublimation is nearly symmetric with a slight advantage for the cryptic region. After Ls=220° the anti-cryptic region sublimation is stronger. Those two phases are not balanced such that there is 22% ± 9 more mass the anti-cryptic region, arguing for more snow precipitation. We compare those results with the MOLA height measurements. Finally we discuss implications for the Martian atmosphere about general circulation and gas tracers, e.g. Ar. |
| Keywords: | Mars Ice Atmosphere Seasonal South Polar Cap Cryptic region Non-condensable gas |
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