基于WaTEM/SEDEM模型的洮河源区土壤侵蚀产沙模拟及其空间驱动力分析

目的]全面认识长时间尺度的土壤侵蚀时空变化及其影响因素对土壤侵蚀治理具有重要意义。探究流域1998—2018年土壤侵蚀和产沙时空变化特征及其空间驱动力因子，为洮河源区流域的水土治理提供科学理论依据。方法]以洮河源区流域为研究区，基于碌曲站实测输沙数据以及植被NDVI数据，通过WaTEM/SEDEM模型结合重心模型分析流域侵蚀产沙时空变化特征，进一步采用地理探测器方法探究其空间驱动力因子。结果]洮河源区的土壤产沙模数由1998年的33.81 t/(hm²·a)增加至2018年的48.59 t/(hm²·a);土壤侵蚀强度主要以微度侵蚀为主，其次是极强侵蚀和轻度侵蚀，剧烈、强烈和中度侵蚀占比最小。侵蚀较强区域分布在高山地带；侵蚀较微弱的区域分布在中部的河谷地区和海拔较低的区域。流域内地形等级和植被覆盖度对土壤侵蚀影响最大，q值分别为0.359,0.183,流域侵蚀模数随地形位等级增大而增大，随植被覆盖度的增大而减少。1998—2003年和2008—2013年这两个时段，土壤侵蚀重心向东南方向移动，2003—2008年侵蚀重心向西北方向移动，...

Simulation and Space Driving Force Analysis of Soil Erosion and Sediment Production in Taohe Source Area Based on WaTEM/SEDEM Model

Objective]A comprehensive understanding of the spatial and temporal changes of soil erosion at long time scales and its influencing factors is of great significance to soil erosion management. The spatial and temporal change characteristics of soil erosion and sediment production in the watershed from 1998 to 2018 and their spatial driving factors were exploreed to provide scientific theoretical basis for the soil and water management in the Taohe River source area watershed. Methods] The Taohe River source area watershed was taken as the study area. Based on the measured sediment transport data from Luqu station and vegetation NDVI data, the spatial and temporal variation characteristics of watershed erosion and sediment production were analyzed by the WaTEM/SEDEM model in combination with the center of gravity model, and the spatial driving factors were further explored by using the geographic detector. Results] The sediment production modulus in the source area of the Taohe River increased from 33.81 t/(hm²·a)in 1998 to 48.59 t/(hm²·a)in 2018. The soil erosion intensity was dominated by slight erosion, followed by extreme intensity and mild erosion, and the proportion of severe, intense and moderate erosion was the smallest. The areas with stronger erosion distributed in the alpine zone. The areas with weaker erosion distributed in the central valley area and the lower elevation area. Topographic grade and vegetation cover within the watershed had the greatest impact on soil erosion, with q values of 0.359 and 0.183, respectively. The erosion modulus of the watershed increased with the increase of the topographic level and decreased with the increase of vegetation cover. In the two periods of 1998—2003 and 2008—2013, the soil erosion gravity center moved to the southeast, in 2003—2008, the erosion gravity center moved to the northwest, and in 2013—2018, it moved to the north. Conclusion] The erosion of the Taohe River source area watershed as a whole showed a deterioration trend from 1998 to 2018, and its spatial driving forces were mainly the topographic position index and vegetation cover factor. The results of the study indicate that the projects of returning pasture to grass should be vigorously developed and ecological vegetation construction should be actively carried out in the future.