Abstract:
Atmospheric dust, through its interaction with incoming solar and outgoing infrared energy, plays an important role in
regulating the climate of Mars and in forcing atmospheric dynamics. Since the lifting of dust from the surface is fundamentally
a result of atmospheric circulations, 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 mean
meridional circulation (Hadley Cell) 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. Furthermore, the importance of developing a quasi-balanced
(e.g., vortical) circulation to the growth and maintenance of disturbances is demonstrated. Finally, the close analogy between
the dust feedback process of Mars and the Wind-Induced Sensible Heat Exchange (WISHE) hypothesis for terrestrial hurricane
intensification is discussed.