Title:	The WEIRD Dust Storm Dynamics of Mars
Speaker:	Scot C. R. Rafkin, Department of Space Studies, Southwest Research Institute, Boulder CO
Time:	Tuesday, 20^th  December, 2011 at 11:15
Place:	Building 1525, room 323

Abstract

Atmospheric dust plays an important role in regulating the climate of Mars through radiative processes. The influence of dust on the deposition of incoming solar energy and outgoing infrared radiation also impacts atmospheric dynamics.  The lifting of dust from the surface is fundamentally a result of atmospheric circulations, so there is the potential for feedback between atmospheric dynamics, dust lifting processes, and the radiative perturbations that ensue.  Previous studies have investigated the effect of atmospheric dust on the general circulation and the growth rate of dynamic instabilities that might result from vertical gradients of dust concentration.   Other studies have investigated the origin of dust disturbances resulting from atmospheric circulations, but without consideration of how the lifted dust may influence the parent atmospheric circulation.   In this talk, I will present results of numerical studies designed to explicitly test and quantify the feedback between atmospheric dust disturbances and the dust lifted from the surface.  It is shown that in all but trivial cases, there is a positive feedback between atmospheric circulations and lifted dust.  The feedback magnitude, however, is highly dependent upon the dust lifting physics, the atmospheric thermodynamic structure, solar flux, and latitude.  The Wind-Enhanced Interaction of Radiation and Dust (WEIRD) for Martian dust storms is presented as an analogy to the Wind-Induced Sensible Heat Exchange (WISHE) hypothesis for terrestrial hurricane intensification.

                                                                                                                                               Jon Merrison