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A. D. Toigo (Cornell University), M. I. Richardson (California Insitute of Technology)
The Mars Exploration Rovers: A Meteorological Tale of Four Landing Sites
In order to support landing site selection for the Mars Exploration Rovers (MER), due for launch in mid-2003, we have conducted mesoscale simulations of the meteorology at four sites using the Mars MM5 [Toigo and Richardson, 2001]. The simulations at the four diverse sites highlight interesting dynamical phenomena related to convection and topographic control of flow. The Hematite region (2S, 6W), sitting in the cratered southern plains, shows a large scale diurnal cycle of winds that are primarily tidal. Embedded within this flow during the daytime hours of peak heating are convective motions displaying classic hexagonal cellular behavior. The convection is initiated over locally high topography, but becomes detached and migrates during the late afternoon. The Gusev Crater site (15S, 175E) displays similar tidal and cellular convective behavior to the Hematite site, but also begins to show evidence for channeling of flow by Ma'adim Vallis. Persistent slope flow is also observed into and out of the crater. The Eos Chasma (13S, 41W) and Melas Chasma (9S, 77W) sites are both within the Valles Marineris system, with Eos Chasma being at the eastern end of the main canyon system. Both sites show very strong channeling of flow, with canyon floor flow in substantially different direction to that on the surrounding plains. Significant flow into and out of the canyons is also indicated in response to diurnal cycles of heating. Adding to the effects of topography is the strong contrast in thermal inertia between the canyon floor and the plains. In all cases, we gauge the predicted wind speeds and vertical shears at the landing times and locations to be quite modest, at the extreme not more than 10 m/s per km. Given the interesting flow behavior in the canyon systems, we very much hope for one of the rovers to explore the depths of Valles Marineris.