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

The Mars regional atmospheric modeling system (MRAMS) is introduced, and se lected model results are presented and compared with landed meteorological data when possible. MRAMS is descended from a nonhydrostatic Earth mesoscal e and cloud-scale model that is widely used for forecasting weather and sim ulating atmospheric systems over complex terrain. Mesoscale models such as MRAMS are ideal tools for making use of the high-resolution data sets arriv ing from Mars Global Surveyor experiments. Simulation of the Mars Pathfinde r (MPF) landing site at L-s = 142 using 1/2 degree Mars orbiter laser altim eter (MOLA)-derived topography and thermal emission spectrometer thermal in ertia is shown to be in good agreement with observed near-surface temperatu re, pressure, and wind direction. Simulations of topographically induced th ermal circulations and mountain-induced gravity waves are shown to be consi stent with theory and earlier studies that tie large-amplitude mountain wav es 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 kinet ic energy, and vertical velocity variance. The model results suggest that t he martian atmosphere is roughly two to three times more turbulent than the terrestrial atmosphere during the afternoon, but fluxes are roughly an ord er of magnitude smaller due to the lower density. Dust-devil-like circulati ons 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 process es inferred through Mars Orbiter Camera imagery of Big Crater, located near the MPF landing site. (C) 2001 Academic Press.