流域分布式侵蚀学坡长的估算方法研究

Research on the estimation of slope length in distributed watershed erosion

坡长是USLE/RUSLE应用到流域尺度上较难提取的因子。本文从理论上对坡长进行分析,提出以流域分布式侵蚀坡长来反映地形因子的坡长值,并采用迭代累积的算法提取坡长,同时考虑了侵蚀、沉积、沟道,较完整地实现了坡长的计算条件。对实例进行计算、分析,并同已有估算方法进行了对比。该方法有效地表达了坡长与地形的相关关系,计算结果准确,空间分布合理,适合于在流域和区域尺度上基于DEM对地形因子进行提取与分析。

Slope length is a factor which is hard to be extracted when USLE/RUSLE is applied to the watershed scale. This paper analyzes theoretically and proposes the distributed watershed erosion slope length to reflect the real value of slope length in topographic factor and using the accumulative slope length algorithm to extract Distributed Watershed Erosion Slope Length from DEM data considering the position of erosion, sedimentation, and channel networks. This method is applied to the Xiannangou catchment. The result shows that it is effective in expressing the relationship between slope length and the terrain with accurate outcomes and reasonable special distribution. This method is suitable for extracting and analyzing terrain factors based on DEM in watershed or regional scale.