The Mars regional atmospheric modeling system: Model description and selected simulations

The Mars regional atmospheric modeling system (MRAMS) is introduced, and selected model results are presented and compared with landed meteorological data when possible. MRAMS is descended from a nonhydrostatic Earth mesoscale and cloud-scale model that is widely used for forecasting weather and simulating atmospheric systems over complex terrain. Mesoscale models such as MRAMS are ideal tools for making use of the high-resolution data sets arriving from Mars Global Surveyor experiments. Simulation of the Mars Pathfinder (MPF) landing site at L-s = 142 using 1/2 degree Mars orbiter laser altimeter (MOLA)-derived topography and thermal emission spectrometer thermal inertia is shown to be in good agreement with observed near-surface temperature, pressure, and wind direction. Simulations of topographically induced thermal circulations and mountain-induced gravity waves are shown to be consistent with theory and earlier studies that tie large-amplitude mountain waves to strong winds capable of producing dust streaks and local dust-lifting events. A large eddy simulation of the convective boundary layer provides estimates of vertical profiles of heat flux, momentum flux, turbulent kinetic energy, and vertical velocity variance. The model results suggest that the martian atmosphere is roughly two to three times more turbulent than the terrestrial atmosphere during the afternoon, but fluxes are roughly an order of magnitude smaller due to the lower density. Dust-devil-like circulations are also predicted in the large eddy simulation. Finally, a simulation that examines atmosphere-surface interactions near Big Crater is discussed. Predicted surface wind stress patterns are consistent with aeolian processes inferred through Mars Orbiter Camera imagery of Big Crater, located near the MPF landing site. (C) 2001 Academic Press.