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The impact of radiatively active dust on land planet climate

Presentation #406.02 in the session “Exoplanets and Systems: Terrestrial Planet Atmospheres 2”.

Published onOct 26, 2020
The impact of radiatively active dust on land planet climate

Atmospheric mineral dust represents a critical source of variability in planetary climate. Dust radiative feedbacks can alter large and local scale dynamics, alternatively warm or cool global temperatures and modify the dust cycle itself. On present-day Mars, radiatively active dust may drive storm growth from local to global scales and has been demonstrated to impact both local winds as well as the zonal circulation. On arid, land planets with a large fraction of desiccated soils, the impact of dust may be further heightened. Here, we use the NASA Ames FV3 model with a fully interactive dust cycle to investigate the impact of radiatively active dust on a Mars-like exoplanet when the solar irradiance is altered. At Earth insolation, passive dust simulations are recognizably Mars-like. However, when radiatively active dust is added, the climate is hugely altered. In particular, we find that 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 controlled by radiatively active dust. We consider the impact of dust on potential habitability, including long-term water stability, surface light limits and, if dust is required to shade surfaces, the possibility for periods of low dust and surface sterilization.

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