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Title: Validation of SWEEP for creep, saltation, and suspension in a desert-oasis ecotone

item PI, HUAWEI - Chinese Academy Of Sciences
item Sharratt, Brenton
item FENG, GARY - US Department Of Agriculture (USDA)
item LEI, JIAQIANG - Chinese Academy Of Sciences
item LI, XINHU - Chinese Academy Of Sciences
item ZHENG, ZEHAO - Chinese Academy Of Sciences

Submitted to: Aeolian Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/28/2016
Publication Date: 2/10/2016
Citation: Pi, H., Sharratt, B.S., Feng, G., Lei, J., Li, X., Zheng, Z. 2016. Validation of SWEEP for creep, saltation, and suspension in a desert-oasis ecotone. Aeolian Research. 20:157-168.

Interpretive Summary: The SWEEP model has been developed by the USDA-ARS to simulate wind erosion. However, the model has not been tested for simulating wind erosion transport processes in a desert environment. We determined that SWEEP correctly simulates total sand transport and transport of the smallest sand fraction during high winds. SWEEP, however, overestimated transport of larger particles saltating along the desert surface. Overestimation of saltation was compensated for by underestimation of the largest particles creeping along the surface. The results suggest that geographers and earth scientists can use SWEEP with confidence for simulating wind erosion of desert landscapes around the world.

Technical Abstract: Wind erosion in the desert-oasis ecotone can accelerate desertification and thus impacts oasis ecological security. Little is known about the susceptibility of the desert-oasis ecotone to wind erosion in the Tarim Basin even though the ecotone is a major source of windblown dust in China. The objective of this study was to test the performance of the Single-event Wind Erosion Evaluation Program (SWEEP) in simulating sand transport associated with creep, saltation, and suspension in a desert-oasis ecotone. Wind erosion processes associated with creep, saltation, and suspension were measured and simulated in a desert-oasis ecotone located in the northern Tarim Basin. Horizontal sand transport was measured over discrete sampling periods during the spring wind erosion seasons of 2012 and 2013. The model appeared to adequately simulate total sand transport (measured sand transport ranged from 14.7 to 252.7 kg m-1 across sample periods) as a result of high values for the index of agreement (d > 0.7). The adequate agreement of the SWEEP in simulating total sand transport was due to the good performance of the model in simulating suspension. The SWEEP model, however, inadequately simulated creep and saltation based upon low values for d (0.61 and 0.64, respectively). The slope estimates of the regression between simulated and measured creep and saltation and difference of mean suggested that the SWEEP underestimated creep and overestimated saltation. Total sand transport was not influenced by underestimation of creep because creep constituted a small proportion (0.13%) of the simulated total sand flux. Inadequacies to simulate creep and saltation separately may be offset in part by simulating these components together in SWEEP and thus provide reasonable estimates of total sand transport in a desert-oasis environment.