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J.R. Murphy (New Mexico State University), S. Larsen, H. Joergensen (Risoe National Lab, Denmark), J.T. Schofield (Jet Propulsion Laboratory)
Derivation of and subsequent analyses of measured martian surface wind speeds at the Mars Pathfinder lander site will be presented. It will be demonstrated that efforts to date indicate difficulty in deriving reliable wind speeds during convective portions of the sol. At night, however, wind speeds are reliable and the derived winds indicate a variety of phenomena.
Winds obtained from late afternoon through early morning indicate recurrent episodes of turbulence, manifested as increased wind speeds and increased near-surface air temperatures suggestive of vertical mixing in a thermally stable environment. Variations of wind direction and speed through the course of the sol illustrate indicate the presence of local and regional control at Pathfinder’s northern subtropical location, with nighttime down slope flows being prominent.
Daytime wind speeds, though quantitatively suspect, do provide, in conjunction with measured wind direction, information regarding the dynamics of small-scale phenomena (convective vortices) as well as seasonal weather variations towards the end of the 83 sol mission. Wind speeds derived during the passage of convective vortices might surpass the speeds required (~30 meters per second) to lift dust from the surface. Winds and temperatures obtained during the final ~10 sols of the mission suggest a change in the weather regime present at the lander site, suggestive of a transition from a summer to autumn ‘pattern’. Comparison will be made with Viking lander 1 meteorological data where appropriate.
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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.