基于M-DEM的黄土人工锄耕坡面水系提取及其分形计算

M-DEM-based stream extraction and fractal dimension calculation for artificial backhoe cultivated loess slope

通过构建黄土人工锄耕(AB)坡面微地形数字高程模型(M-DEM),设置不同的集水阈值提取微地形水系,并运用网格法计算相应的水系分维值。结果表明:当集水阈值为25时,所提取的水系网与实际情况最为相符,拟合程度最高(0.971),相应的水系分维数1.087可作为AB坡面微地形水系分维值。本研究为黄土耕作坡面微地形水系分维的研究提供方法指导,为进一步揭示土壤侵蚀机理提供数据支持。

In this paper a M-DEM for artificial backhoe cultivated loess slopes is built based on laboratory experiment.Then,the stream networks for different catchment thresholds（minimum river length） are extracted with the help of ArcGIS 9.3 soft package.Correspondingly,the fractal dimensions are calculated based on the grid method.The results show that when the catchment threshold is 25,the extracted stream network fits the actual surface microtopography best with a highest coefficient of determination（R2=0.971） and the fractal dimension is D=1.087.Generally,a methodology about a microtopographic stream with its fractal dimension is illustrated,and it is safe to be adopted for further surface microtopographic research.