The Impact of Radiatively Active Dust on Land Planet Climate

Atmospheric aerosols represent a significant source of climate variability and should be carefully considered in studies of exoplanetary climatologies. On land planets with limited water, desiccated soils may act as a major source of mineral dust and, as on present-day Mars, atmospheric dust can radiatively modify local and large scale dynamics, atmospheric thermal gradients, etc. However, simulating the impact of atmospheric dust is non-trivial, in particular since radiatively active dust can generate feedbacks that alternatively suppress or enhance further lifting. Here, we use the NASA Ames FV3 general circulation model for present day Mars with fully interactive dust to investigate the impact on climate of radiatively active dust on Mars-like land planet at Earth insolation. We find that radiatively active dust significantly modifies global atmospheric dynamics. Radiative heating in the summer polar middle atmosphere strengthens the seasonal Hadley circulation, which modifies the spatial distribution and magnitude of surface winds that control dust lifting. We define a new dust lifting regime at high insolation controlled to first order by radiatively active dust. While the diurnal tide is reduced, sub-diurnal components of the tide that respond to the global average dust heating are strengthened. The semi- and ter-diurnal tides are critical for the formation of summer hemisphere Ferrel cells that transport dust to the middle atmosphere.