  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{\deg} to 220{\deg}, the
sublimation is nearly symmetric with a slight advantage for the cryptic region.
After Ls=220{\deg} 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.
