DPS 35th Meeting, 1-6 September 2003
Session 3. Mars Atmosphere I
Oral, Chairs: T. A. Livengood and A. Colaprete, Tuesday, September 2, 2003, 10:30am-12:00noon, DeAnza I-II

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[3.01] Cloud-tracked Winds for the First MGS Mapping Year

H. Wang, A. Ingersoll (Caltech)

We have measured winds using cloud motion in consecutive Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle global map swaths taken during the first mapping year (Ls 135\arcdeg-360\arcdeg-111\arcdeg). We present a total of ~11,200 wind vectors collected in the north polar region during Ls 135\arcdeg-195\arcdeg (late summer/early fall) and Ls 20\arcdeg-55\arcdeg (mid spring), and in the south polar region during Ls 337\arcdeg-10\arcdeg (late summer/early fall). For cases with good coverage, we also present the derived mean zonal and meridional winds and the associated eddies. The speed of the zonal winds in 60\arcdegN-70\arcdegN increases at ~0.6 m/s/\arcdegLs in late northern summer, and that in 60\arcdegS-70\arcdegS increases at a rate of ~0.7 m/s/\arcdegLs in late southern summer. The latitudinal distribution of zonal wind within 50\arcdegN-75\arcdegN from mid northern summer to early northern fall indicates that winds at higher latitudes are generally weaker than those at lower latitudes, but the rate of increase with time is faster at higher latitudes. There is a cyclonic gyre in the 90\arcdegW-0\arcdeg-30\arcdegE sector in the north polar region. There are large-scale waves in the weekly mean meridional wind and in the bi-weekly mean eddy momentum flux and eddy kinetic energy fields in the north polar region from mid to late summer. The cloud-tracked winds in the north are generally consistent with winds calculated by general circulation model at the water condensation level derived from MGS Thermal Emission Spectrometer (TES) observations, but appear stronger than the gradient winds derived from TES assuming no flow at the surface.

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.