31st Annual Meeting of the DPS, October 1999
Session 48. Mars Atmospheres Posters
Poster Group II, Thursday-Friday, October 14, 1999, , Kursaal Center

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[48.03] On northern polar cap mesoscale circulations and associated water transport phenomena

T. Siili (FMI/GEO), D. S. Bass (SwRI), H. Savij\"{a}rvi (DMUH)

During the retreat of the northern seasonal polar ice cap the very different optical and thermal characteristics of ice-free regolith, CO2 and H2O ice coverages together with their seasonally changing horizontal configurations drive an interesting set of terrain-induced mesoscale circulations. In simulations using flat topography these circulations manifest themselves as separate or merged daytime circulation cells above the edges of different ice coverage regions. Slope winds driven by the the regional topography are also probably ubiquituous.

The mesoscale circulation patterns may play a role in the polar water transport phenomena; the circulation cell can plausibly return water sublimed from exposed H2O ice to above the CO2 or H2O ice for recondensation and deposition. The albedo of the interior of the polar cap has been observed to brighten and the brightening may be caused by the accumulation of fresh H2O ice as described above.

We have used the Department of Meteorology 2-D Mars Mesoscale Circulation Model --- a x-\sigma coordinate system primitive equation model --- to simulate some of the plausible northern polar cap edge region spring-summer (Ls= 50\circ\ldots120\circ) mesoscale circulations and the associated water transport characteristics.

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

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