Spatiotemporal distribution and variation of wind erosion over the Tibetan Plateau based on a coupled land-surface wind-erosion model

Abstract

Wind erosion has notable impacts on ecology, water supply and regional climate, but its distributions and long-term changes are still poorly quantified for the Tibetan Plateau (TP). This study develops a coupled land-surface wind-erosion model (HRLDAS-WEPS) in two dimensions horizontally to analyze wind-erosion distributions and its temporal variations under the climate change in 1979–2015 over the entire TP. Two model enhancements are also used, including the application of MODIS vegetation datasets and the optimization of snow-cover parameterizations. Evaluation results indicate that the enhanced coupled model can generally represent the wind-erosion distributions over the TP, being mainly located in the arid and semi-arid areas and occurring in winter and spring, as compared with station observations and satellite datasets. In 1979–2015, wind erosion has a significant (P < 0.01) decreasing trend of −0.54 kg m−2 yr−1 for annual total soil loss averaged over the arid and semi-arid areas of the TP, which is mainly due to the significant (P < 0.01) declining wind speed and increasing soil moisture. The severest wind-erosion reduction is located to the northwest of the 200 mm precipitation line and the Qaidam Basin. Furthermore, a significant turning point of wind-erosion variation is found in 1992. Specifically, wind erosion over the TP decreases from 1979 to 1991 (−1.26 kg m−2 yr−1), and then stays at a low level with a slight increase (0.08 kg m−2 yr−1) since 1993. This is probably due to the abrupt change of wind speed over the TP in 1991.