DPS 2001 meeting, November 2001
Session 19. Mars Atmosphere Posters
Displayed, 9:00am Tuesday - 3:00pm Saturday, Highlighted, Wednesday, November 28, 2001, 10:30am-12:30pm, French Market Exhibit Hall

## [19.06] Winds in a Martian northern polar valley geometry

T. Siili (FMI/GEO), H. Savijarvi, A. Maattanen (UH/PHYS/ATM)

In this work we have investigated mesoscale winds in an idealised valley geometry using simulations with a University of Helsinki Division of Atmospheric Sciences (UH/ATM) 2-D high-resolution Mars Mesoscale Circulation Model (MMCM). Our focus is on northern polar terrain --- especially the Chasma Borealis region --- hence simulations have been carried out in setups corresponding to high northern latitudes (\phi > 70\circ). Seasons correspond to northern spring and summer (Ls = 0--180\circ), to include seasonal carbon dioxide ice cover and to obtain most pronounced thermal contrasts between ice-free regolith and ice-covered terrains.

Comparisons between configurations with different ice coverages (water and carbon dioxide) have been performed to distinguish between the roles of slope (especially the sustained katabatic flows down icy slopes) and ice edge forcings as well as to investigate the significance of a resulting valley floor heat island'' caused by exposed regolith surrounded by ice-covered slopes. The influence of along-valley flow has also been looked into.

Funding for this work was provided by the Academy of Finland (project 51441) and is gratefully acknowledged.