黄河粗泥沙集中来源区区域地形因子比较研究

Comparative Study for Regional Terrain Factors in Coarse Sand Source Area of Loess Plateau

在黄河粗泥沙集中来源区的清水川流域,以1∶10 000比例尺地形图上的小流域为基本单元,在1∶250 000比例尺DEM上提取地表起伏度、高程变异系数和等高线密度等区域土壤侵蚀地形因子,以1∶10 000比例尺计算的地形因子为真值,拟合各区域土壤侵蚀地形因子的计算方法。结果表明,等高线密度是合适的区域土壤侵蚀地形因子计算指标。应用该方法在皇甫川下游进行检验,模拟结果误差小于10%,效果良好,可作为土壤侵蚀区域地形因子计算时指标选择的参考。

By taking small watershed on the 1∶10 000 scaled topographic map of Qingshuichuan basin in the coarse sand source area of the Loess Plateau as a basic cell,terrain factors for regional soil erosion,including surface relief,variance coefficient,and contour line density,are extracted from 1∶250 000 scaled digital elevation model.The terrain factors calculated from the 1∶10 000 scaled map are regarded as truth values to fit the calculation method of terrain factors for soil erosion in each region.Results showed that only the contour line density is an appropriate index of terrain factors for regional soil erosion.The method has been applied in the lower reaches of Huangpuchuan River,with the deviation less than 10%.Such a good simulation result indicates that the method can be used as a reference to index determination in the calculation of regional terrain factor for soil erosion.