DPS Pasadena Meeting 2000, 23-27 October 2000
Session 51. Mars Atmosphere Posters
Displayed, 1:00pm, Monday - 1:00pm, Friday, Highlighted Tuesday and Thursday, 3:30-6:30pm, C101-C105, C211

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[51.03] On mesoscale circulations and water transport around the northern polar cap

T. Siili (FMI/GEO), D. S. Bass (SwRI), H. Savijärvi (DMUH)

To date, we have simulated surface-induced mesoscale circulation patterns in the northern polar cap edge regions in spring-summer seasons (Ls = 50 - 120\circ), using sets of surface properties such as topography h, albedo a, thermal inertia I, and CO2 ice coverage FCO2). Past simulations used semi-idealised parameters that corresponded to a single longitude sector along the cap edge at, \emph{e.g.}, 180-200\circW. The model used is the University of Helsinki Department of Meteorology (DMUH) 2-D Mars Mesoscale Circulation Model (MMCM). The roles of slope winds, ice edge, a and I variation flows as well as the atmospheric H2O fields have been investigated. The results suggest that the characteristic flow pattern is consistent with strong near-surface off-cap katabatic winds with a modest diurnal variation. There is resemblance with, \emph{e.g.}, the patterns occurring in Antarctic regions on Earth.

In this work we have studied the longitudinal variation of the cap edge mesoscale circulation characteristics and their relationship to the H2O cycle. We have extended our study by undertaking simulations of a variety of longitudes around the edge of the northern polar cap. MMCM simulations of four longitude sectors between 90\circW \ldots 330\circ at Ls = (70\circ, 80\circ, 90\circ) have been performed. Chasma Borealis is excluded due to the model's limitation to approximately 2-D topographies. For these simulations, MGS/MOLA topography was used, and albedo, thermal inertia, and surface temperature parameters were constrained by using orbital observations from IRTM and TES as appropriate.

The author(s) of this abstract have provided an email address for comments about the abstract: mailto:Tero.Siili@fmi.fi

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