Monday, 8 January 2018: 3:30 PM
Room 9AB (ACC) (Austin, Texas)
Dust aerosols can be lofted from dry surface soils/deserts into the atmosphere by mechanical means associated with strong surface winds. Intense dust lofting events can substantially impact visibility and solar insolation through absorption and scattering of downwelling shortwave radiation. Dust-induced changes to solar insolation can impact the development and intensity of atmospheric phenomena that are initiated by daytime heating. As such, numerical model prediction of dust episodes in dust prone areas relies upon robust dust lofting methodologies, parameterizations and datasets that best simulate the amount and location of lofted dust. In this study, we have examined the dust lofting capabilities of three lofting methodologies: (1) idealized lofting of dust wherever bare soil exists, (2) application of a 1-deg x 1-deg dust erodible fraction dataset, and (3) idealized lofting constrained by a high resolution dataset identifying known lofting locations. In each methodology dust lofting is a function of threshold friction velocity and soil moisture. We will present results from simulations that were performed of a dust lofting event that occurred over the Arabian Peninsula from Aug 2-4, 2016. The various lofting methodologies result in large differences in the mass of dust that is lofted from the surface and transported throughout the region. The variability in predicted dust mass impacts the solar insolation, and thus, the surface fluxes and sea-breeze development, which then subsequently impacts additional dust lofting. Implications for future representation of dust processes in mesoscale, regional and climate models will be presented.
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