Modeling of Dust: Incorporating the Wind Erosion Prediction System (WEPS) into a Regional Air Quality Modeling System

SERENA H. CHUNG (1), Jincheng Gao (2), Larry E. Wagner (3), Joseph Vaughan (1), Drew A. Polley (1), Timothy M. VanReken (1), Brian K. Lamb (1)

(1) Washington State University, Pullman (2) Kansas State University, Manhattan (3) United States Department of Agriculture-Agricultural Research Service Engineering and Wind Erosion Unit, Manhattan, Kansas

     Abstract Number: 357
     Last modified: May 10, 2010

Abstract
Wind erosion of soil is a major concern for the agricultural community, as it removes the most fertile part of the soil and thus degrades productivity. Furthermore, the wind-induced suspension of eroded soil particles results in dust emissions to the atmosphere, which contributes to poor air quality, reduced visibility, and climate change. An important aspect of understanding the atmospheric impacts of agricultural activities is the ability to model windblown dust emissions within the framework of a regional air quality system. The Wind Erosion Prediction System (WEPS) is the new standard tool for treating erosion from agricultural fields. It is a process-based model and represents a significant improvement over previous windblown dust modeling algorithms that were highly empirical. WEPS includes several submodels that combine to provide an integrative approach for modeling soil erosion on agricultural land, accounting for crop growth, crop management practices, soil conditions, and surface cover. WEPS was originally intended for soil conservation applications and is designed to simulate conditions of a single field over multiple years. Applying WEPS to a regional air quality modeling framework requires that the model be applied to a fixed Eulerian grid. In this work, all submodels in WEPS have been modified so that it can be incorporated into a regional air quality forecasting system, using meteorological results from the Weather Research and Forecasting (WRF) mesoscale model as input and providing PM10 emissions for the CMAQ chemical transport model. The WRF/CMAQ/WEPS modeling framework is evaluated using ambient PM10 data and is used to study the impact of windblown dust on air quality in the Columbia Plateau region of the Pacific Northwest.