西南高山峡谷区水力侵蚀时空变化及其驱动力.

[Objective] The aims of this study are to determine the spatial distribution of water erosion and its spatial-temporal variation in southwest alpine-canyon area, to explore driving mechanism of water erosion in study area, and to provide countermeasures for regional soil erosion and water loss control. [Methods] Based on GIS and RUSLE model, the spatial and temporal variation and driving mechanism of water erosion in southwest alpine-canyon area were analyzed by using the method of the Theil-Sen trend analysis. Mann- Kendall significance test and random forest model. [Results (1) The ratio of light erosion and mild erosion was over 78.05%. (2) Generally, during the period of 2000 to 2020, the range of water erosion amount varied between 4.606 3×108 t and 1.487 4×109 t and the annual value was 7.9664×108t. The range of rainfall erosion factor amount varied between 125.11 MJ mm/(hm².h.a) and 249,93 MJ mm/(hm² ha) and the annual value was 186.71 MJ mm/(hm²h.a). The range of vegetation coverage and management factor varied between 0.37 and 0.70 and the average value for years was 0.48. (3) Topographic factors was with the highest contribution to explain spatial variation of water erosion, accounting for 41%, followed by vegetation coverage and management factors, rainfall erosion factor, soil erodibility factor, soil and water conservation measure factor, accounting for 24%, 16%, 12%, and 8%, respectively. Moreover, spatial variation contribution of each factor varied with the soil and water conservation zone. [Conclusion] The severe erosion areas mainly distributed in the southern part of Eastern Xizang & West Sichuan Ecological Maintenance & Water Conservation Region. Eastern and northwest part of Southeast Xizang arctic-alpine Ecological Maintenance Region. Topographic factors and vegetation coverage and management factors was the main driving factors. In the Ecological Maintenance and Water Conservation Zone of Eastern Xizang & Western Sichuan, the Southeast Xizang Ecological Maintenance Arctic alpine Zone and the Northwest Yunnan Ecological Maintenance Zone, the measures that would improve the vegetation cover to increase the soil anti-erodibility was suggested. In the North Yunnan & Southwest Sichuan Water Storage and Soil Conservation Zone, vegetation cover should be improved while appropriate soil and water conservation measures could be placed. [ABSTRACT FROM AUTHOR]