Simulation of dust activities in the southern high latitudes of Mars

Abstract

Annual occurrence of dust activities in the southern high-latitude region around the southern solstice period have been observed for many Martian years. Theses dust events occur near the southern cap-edge region and play an important role in the observed dust climate. However, they generally cannot be simulated in the existing Mars general circulation models. In this study, an approach of parameterization has been applied to the Mars climate model MarsWRF in which the dust lifting threshold stress is adjusted in according to the surface temperature difference between the regolith and the ice in the southern polar region. By this approach, dust events in the southern cap-edge region have been simulated around the southern solstice period. As a result, the simulated temperature in the southern high-latitude region is increased and the resulting vertical temperature profile is closer to that from observation. In addition, westward propagating dust events as observed in a previous study have been simulated, with a propagating speed similar to that observed. Results of the numerical experiments suggest that the flow associated with the sublimation of the CO 2 ice in the southern cap edge is important to the occurrence and propagation of these dust events in this region. • Dust activities near the southern cap edge have been simulated with the interactive dust approach. • A parameterization scheme of cap-edge dust is proposed. • Generation of cap-edge dust is dependent on ice-regolith temperature difference. • Sublimation flow is important to the generation of cap-edge dust.