Seasonal CO2 polar caps on Mars: geomorphological and hyperspectral imaging evidences

Frédéric Schmidt

(IDES, Université Paris-Sud, Orsay, France)

Abstract

The polar condensation/sublimation of CO₂, that involve more than one fourth of the atmosphere mass, is the major Martian climatic cycle. Early observations in the visible and thermal infrared range have shown that the sublimation of the Seasonal South Polar Cap is not symmetric around the geographic South Pole. The origin of this asymmetry is still a mystery but seems to be related to geomorphological features such as "spiders" and "jets".

I will introduce the observations by the imaging spectrometer OMEGA (Mars Express) in the near-infrared that unambiguously detect the presence of CO₂ ice at the surface and estimate the surface physical properties. I will also present the relationship between CO₂ ice properties and the jets activity and discuss the consequences for the Martian climate.