14.2 Simulating Southwestern U.S. Desert Dust Influences on Supercell Thunderstorms

Thursday, 6 August 2015: 8:30 AM
Republic Ballroom AB (Sheraton Boston )
David Lerach, University of Northern Colorado, Greeley, CO
Manuscript (769.0 kB)

High-resolution, three-dimensional numerical simulations are performed, in order to evaluate potential southwestern U.S. desert dust impacts on a severe, tornadic storms outbreak that occurred during 15-16 April 2003 near the Texas Panhandle. This work expands on a previous study by making use of the RAMS version 6 model and a sophisticated triple-moment bulk hail microphysics scheme, utilized to more accurately capture dust indirect impacts on storm microphysics, evolution, and resulting cold-pool thermodynamics. A control simulation excludes any dust presence. Sensitivity simulations are performed in order to isolate and quantify potential direct radiative influences by lofted dust as well as indirect microphysical impacts, wherein dust might serve as cloud condensation nuclei (CCN), giant CCN, and ice nuclei during cloud evolution. Analyses will focus on storm initiation, supercell longevity and updraft strength, the evolution of rain and hail size spectra, resulting melting and evaporative cooling rates, and overall impacts on thermodynamic cold pools and the potential for tornadogenesis.
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