HR: 0830h
AN: B21F-0788    [PDF]
TI: Numerical Modeling of Regional Windblown Dust in the Pacific Northwest:Incorporation of an Improved Dust Emission Model
AU: * Sundram, I
EM: irra_t-mohanasu@wsu.edu
AF: Laboratory for Atmospheric Research, Department of Civil & Environmental Enginnering Washington State University, Pullman, WA 99164 United States
AU: Claiborn, C
EM: claiborn@wsu.edu
AF: Laboratory for Atmospheric Research, Department of Civil & Environmental Enginnering Washington State University, Pullman, WA 99164 United States
AU: Strand, T
EM: strand@mail.wsu.edu
AF: Laboratory for Atmospheric Research, Department of Civil & Environmental Enginnering Washington State University, Pullman, WA 99164 United States
AU: Lamb, B
EM: blamb@wsu.edu
AF: Laboratory for Atmospheric Research, Department of Civil & Environmental Enginnering Washington State University, Pullman, WA 99164 United States
AU: Chandler, D
AF: Department of Plants, Soil and Biometeorology, Utah State University, Logan, UT 84322 United States
AU: Saxton, K
EM: ksaxton@wsu.edu
AF: USDA-ARS, L.J. Smith Hall Washington State University, Pullman, WA 99164 United States
AB: Soil erosion by wind is a serious consequence of dryland agriculture in eastern Washington where the main adverse effects are loss of nutrient rich soil, reduced visibility during dust storms and regional air quality impacts in downwind populated areas. A multidisciplinary research effort to study windblown dust in central and eastern Washington was initiated under the Columbia Plateau PM $_{10}$ (CP $^{3}$) program. As part of this study, wind erosion and windblown dust emissions were measured in impacted population centers and a transport and dispersion model was developed for the region. The modeling system includes the use of a prognostic meteorological model, Mesoscale Metorological Model Version 5 (MM5), coupled with the CALMET/CALGRID Eularian modeling pair and a new dust emission module (EMIT-PM), developed specifically for this region from extensive soil sampling, portable wind tunnel measurements and intensive field campaigns. Surface wind observations were integrated into the diagnostic meteorological model, CALMET, along with wind fields generated by MM5 for six dust storm events that occurred in November 1990, October 1991, September 1993, November 1993, August 1996 and September 1999. Area dust emissions were generated using the CALMET wind fields along with detailed soil and land use maps in the EMIT-PM model and these hourly, gridded emissions were then used in CALGRID, which calculated hourly averaged concentrations of PM10 (particulate matter of aerodynamic diameter $<$ 10 $\mu$ m) throughout the modeling domain. The predicted 24-hour average concentrations compared favorably to observed concentrations that were measured at selected locations within the modeling domain. For all the simulated events, with the exception of the August 1996 event, ratios of observed to predicted concentrations were within a range of 0.5 to 6.0. Because these ratios' were obtained without the need for a calibrated dust constant, it appears that the EMIT-PM provides an improved representation of PM $_{10}$ emissions from eroding fields in the Columbia Plateau. The overall robustness of this modeling approach in terms of the computational resources utilized and the prediction accuracy range achieved is encouraging with regards to developing a predictive based system for dust emissions.
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2003 Fall Meeting