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Large Eddy Simulations of the Dusty Martian Convective Boundary Layer with MarsWRF
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  • Zhaopeng Wu,
  • Mark Richardson,
  • Xi Zhang,
  • Jun Cui,
  • Nicholas Heavens,
  • Christopher Lee,
  • Tao Li,
  • Yuan Lian,
  • Claire Newman,
  • Alejandro Soto,
  • Orkun Temel,
  • Anthony Toigo,
  • Marcin Witek
Zhaopeng Wu
Sun Yat-sen University

Corresponding Author:[email protected]

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Mark Richardson
Aeolis Research
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Xi Zhang
University of California Santa Cruz
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Jun Cui
Sun Yat-sen University
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Nicholas Heavens
Space Science Institute
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Christopher Lee
Aeolis Research
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Tao Li
University of Science and Technology of China
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Yuan Lian
Aeolis Research
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Claire Newman
Aeolis Research
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Alejandro Soto
Southwest Research Institute
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Orkun Temel
Royal Observatory of Belgium
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Anthony Toigo
Johns Hopkins University Applied Physics Laboratory
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Marcin Witek
California Institute of Technology
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Abstract

Large eddy simulation (LES) of the Martian convective boundary layer (CBL) with a Mars-adapted version of the Weather Research and Forecasting model (MarsWRF) is used to examine aerosol dust radiative-dynamical feedback upon turbulent mixing. The LES is validated against spacecraft observations and prior modeling. To study dust redistribution by coherent dynamical structures within the CBL, two radiatively-active dust distribution scenarios are used—one in which the dust distribution remains fixed and another in which dust is freely transported by CBL motions. In the fixed dust scenario, increasing atmospheric dust loading shades the surface from sunlight and weakens convection. However, a competing effect emerges in the free dust scenario, resulting from the lateral concentration of dust in updrafts. The resulting enhancement of dust radiative heating in upwelling plumes both generates horizontal thermal contrasts in the CBL and also increases buoyancy production, jointly enhancing CBL convection. We define a dust inhomogeneity index (DII) to quantify how much dust is concentrated in upwelling plumes. If the DII is large enough, the destabilizing effect of lateral heating contrasts can exceed the stabilizing effect of surface shading such that the CBL depth increases with increasing dust optical depth. Thus, under certain combinations of total dust optical depth and the lateral inhomogeneity of dust, a positive feedback may exist among dust optical depth, the vigor and depth of CBL mixing, and—to the extent that dust lifting is controlled by the depth and vigor of CBL mixing—the further lifting of dust from the surface.