HR: 10:50h
AN: A52A-03    [Abstracts]
TI: Airborne Dust Modified the North American Climate During the 1930's Dust Bowl
AU: * O'Brien, T A
EM: tobrien@ucsc.edu
AF: University of California, Santa Cruz -- Department of Earth and Planetary Science, 1156 High St., Santa Cruz, CA 95064, United States
AU: Solmon, F
EM: solf@aero.obs-mip.fr
AF: Laboratoire d'Aérologie, Observatoire Midi-Pyrénées, O.M.P. 14 avenue Edouard Belin, Tolouse, 31400, France
AU: Sloan, L C
EM: lcsloan@pmc.ucsc.edu
AF: University of California, Santa Cruz -- Department of Earth and Planetary Science, 1156 High St., Santa Cruz, CA 95064, United States
AU: Snyder, M A
EM: msnyder@pmc.ucsc.edu
AF: University of California, Santa Cruz -- Department of Earth and Planetary Science, 1156 High St., Santa Cruz, CA 95064, United States
AB: In the 1930's Dust Bowl, drought in Mid-Western North America, in conjunction with wide-scale planting of drought-vulnerable crops, resulted in massive dust storms. The presence of dust in the atmosphere may have directly altered the energy budget of North America by the scattering and absorption of radiation and thus may have acted as a feedback to the regional drought conditions. Through a climate modeling sensitivity study of North American climate investigating the impact of airborne dust during the 1930's (using a regional model, RegCM3), we find that areas with moderate to high dust-loading have reduced surface temperatures (~1K) and reduced evapotranspiration (~0.5 mm/day). We also find spatially-coherent, statistically significant changes in precipitation patterns over eastern North America during Spring, Summer, and Fall: areas gain and lose as much as 2 mm/day of precipitation. We are working on a more detailed analysis to determine the causal relationship(s) between airborne dust and precipitation patterns; we hypothesize that the spatially non-uniform change in the energy budget, caused by dust loading, modifies regional dynamics and indirectly modifies precipitation patterns.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0360 Radiation: transmission and scattering
DE: 0454 Isotopic composition and chemistry (1041, 4870)
DE: 3355 Regional modeling
DE: 9350 North America
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly