Water-ice accumulation rate at Martian South Pole

These images, generated thanks to Martian Global Climate Models (GCMs), provide a comparison between the water-ice accumulation rates in two different periods (present day and 21 500 years ago), corresponding to inversed planetary precession periods.

Present-day map shows a net accumulation of water-ice only at the South Pole itself, where the existence of a CO2 cold-trap forces a local and permanent deposition of water-ice. In the inversed situation (21 500 years ago), the CO2 cold trap has been removed and the pattern of accumulation is only controlled by the precipitation/sublimation of water vapour on an annual average.