دانلود رایگان مقاله اعتبار سنجی از رفت و برگشت برای خزش، جهش، و تعلیق در یک بوممرز بیابان واحه

abstract

Wind erosion in the desert–oasis ecotone can accelerate desertification, but little is known about the susceptibility of the ecotone to wind erosion in the Tarim Basin despite being 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 soil loss as creep, saltation, and suspension in a desert–oasis ecotone. Creep, saltation, and suspension were measured and simulated in a desert–oasis ecotone of the Tarim Basin during discrete periods of high winds in spring 2012 and 2013. The model appeared to adequately simulate total soil loss (ranged from 23 to 2272 g m
2 across sample periods) according to the high index of agreement (d = 0.76). The adequate agreement of the SWEEP in simulating total soil loss was due to the good performance of the model (d = 0.71) in simulating creep plus saltation. The SWEEP model, however, inadequately simulated suspension based upon a low d (60.43). The slope estimates of the regression between simulated and measured suspension and difference of mean suggested that the SWEEP underestimated suspension. The adequate simulation of creep plus saltation thus provides reasonable estimates of total soil loss using SWEEP in a desert–oasis environment.

4. Conclusion

The ability of SWEEP to simulate creep, saltation, and suspension was tested in a desert–oasis ecotone within the Tarim Basin. The SWEEP adequately simulated total soil loss and loss due to creep plus saltation. However, the model appeared to underestimate loss due to suspension. Total soil loss was not influenced by underestimation of suspension because of the relatively small proportion (13%) of suspension in simulated total sediment loss. Creep and saltation are simulated as a single transport component in SWEEP because these processes have limited transport capacity. Aggregate size distribution of the aeolian sand was used, however, to separate creep and saltation. The SWEEP simulated creep and saltation adequately, but only when the measured aggregate size distribution was used to ascertain the percentage of creep-size and saltation-size particles.