|PI, HUAWEI - Chinese Academy Of Sciences
|ZHANG, XIAOXIAO - Chinese Academy Of Sciences
Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2014
Publication Date: 12/1/2014
Citation: Pi, H., Sharratt, B.S., Feng, G., Zhang, X. 2014. Comparison of measured and simulated friction velocity and threshold friction velocity using SWEEP. Soil Science. 179:393-402.
Interpretive Summary: The USDA-ARS Wind Erosion Prediction System (WEPS) was developed to aid in identifying and managing lands highly susceptible to wind erosion, but reasons have not been identified for its failure to simulate erosion during high wind events in the Pacific Northwest region of the United States. WEPS was found to consistently overestimate the measured threshold velocity at which the soil begins to erode, thus resulting in its poor performance. The modeling community can improve the performance of WEPS in regions with loessial soils, like the Pacific Northwest, by modifying parameters that affect the computation of threshold velocity.
Technical Abstract: The Wind Erosion Prediction System (WEPS) was developed by the USDA Agricultural Research Service as a tool to predict wind erosion and assess the influence of control practices on windblown soil loss. Occasional failure of the WEPS erosion submodel (SWEEP) to simulate erosion in the Columbia Plateau region of the Pacific Northwest United States may be due to overestimation of threshold friction velocity (u*t). No definitive work has been conducted to ascertain the cause for the occasional poor performance of SWEEP in the region. Therefore the objective of this study was to assess the performance of SWEEP in estimating friction velocity (u*) and threshold friction velocity u*t. SWEEP begins to simulate erosion when u* exceeds u*t, therefore we compared measured and simulated u* and u*t during high wind events in the Columbia Plateau. SWEEP appeared to both underestimate u* and overestimate u*t during high wind events. Our results suggest that SWEEP is very sensitive to stem area index (SAI) and that performance of SWEEP in estimating u* was better at field sites characterized by lower rather than higher SAI.