Simulation of martian surface conditions with the MarsWRF GCM to assess the deliquescence potential of particular regions on Mars

Abstract

The objective of this work is to establish the Martian regions whose surface conditions are favourable to the deliquescence of salt. This process allows the formation of salt water (a brine) in which life can, under certain conditions, develop. A global scale modelling (MarsWRF Global Circulation Model) is performed to acquire the surface conditions. First, diurnal and seasonal variations for the entire planet are analysed. This shows that the areas meeting the conditions are mainly in the Northern Hemisphere in summer, between 50°N and 50°S in spring and autumn and mainly around the equator in winter. Then, some interesting locations were investigated in more detail. On the one hand, landing sites and on the other, sites where the absorption spectrum revealed the presence of salts. What emerges primarily from this study is that calcium perchlorate is the most likely salt to deliquesce under Martian conditions. For sites located at high latitudes, they can host brines in the first half of the year. Mid-latitude sites in the north allow salt deliquescence throughout the year but the maximum number of hours for which conditions are satisfied is about ten hours around the winter solstice. The same is true for locations near the equator but a hollow period is visible during the autumn and the maximum number of consecutive hours encountering the conditions is lower. In the Southern Hemisphere, only Hale Crater showed surface conditions favourable for the deliquescence of calcium perchlorate. To conclude, many locations have surface conditions allowing salts deliquescence for a determined interval of consecutive hours, but this study does not establish whether during this time brines form and remain stable.