Modeling the Dust Cycle on Mars With the Global Mars Multiscale Model GEM-Mars

The Mars atmosphere General Circulation Model GEM-Mars developed at York University has been used to simulate the dust cycle on Mars. The dynamic core is based on the Canadian operational weather forecast Global Environmental Multiscale NWP Model (GEM 3.3.0). Both dust devils and wind shear lifting schemes are included in the model. The wind shear scheme was modified from the terrestrial Dust Entrainment And Deposition (DEAD) model. This study has explored the two dust lifting schemes, dust radiative transfer, dust dry deposition, and other physical schemes, such as CO2 thermal infrared transfer, CO2 near-infrared absorption, UV-EUV heating, surface force-restore method, turbulence and diffusion, and CO2 condensation schemes. The expanded model has successfully simulated Mars dust cycles in a spontaneous and self-consistent way. Our results agree with observations that: during the perihelion season (roughly southern spring and summer, solar insulation is stronger) the Martian atmosphere is relatively warm and dusty, and during the aphelion season it is relatively cool with less dust. The simulated dust vertical distributions and atmospheric temperatures are generally consistent with the MCS and Phoenix observations. The two dust lifting schemes both contribute to atmospheric dust loading with mechanical lifting scheme triggering dust storms while dust devils keep the atmospheric dust background. However, our simulated dust storms show a regular variability with time and locations every Mars year without inter-annual variability.