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M.R.V. Sta. Maria, S.C.R. Rafkin (San Jose State University)
Simulations of the Tharsis region using the Mars Regional Atmospheric Modeling System (MRAMS) have revealed highly dynamic thermal circulations and intense thermal convection. Daytime upslope and nighttime downslope winds reach 50 m/s. During the daytime, upslope winds, with return flows exceeding 100 m/s, and deep convection above the Tharsis volcanoes produce highly turbulent flow that extends up to 20 km above the surface. Thermal and kinematic fields are shown to be consistent with observed afternoon clouds. Results are also shown to compare favorably with TES and Radio Science temperature soundings. At night, katabatic winds are preceded by an intense and narrow front with turbulent surface stresses sufficient to lift dust and sand. These thermal circulations are presented in the context of light wind streaks found in the lee of topographic barriers. The simulations show modeled wind directions and speeds matching wind streak orientations found in some areas. The agreement over other places, however, is poor, and challenges the hypothesis of dust streak formation. This study is funded by NASA Planetary Atmosphere Program Grant, NAG5-9571.