中文摘要：

降雨侵蚀力简易算法是较大尺度应用USLE／RUSLE进行土壤侵蚀评价研究的必要内容。基于降雨量和降雨时间建立月降雨侵蚀力计算模型，并以陕北黄土丘陵沟壑区为例，进行模型的拟合。结果表明：随着自变量中降雨量和降雨时间表示方式的改变，模型的拟合优度表现出明显的差异；对于不同因变量而言，以∑El30（或lg（∑El30））和以EEI10（或lg（∑E10））为因变量的模型拟合优度在整体上比较接近甚至相同，而以∑E60I10（或lg（∑E60I10））为因变量的模型拟合优度在整体上略低；就尺度效应而言，在时间尺度上，整个汛期的模型拟合优度低于1个月份或多个月份模型的拟合优度，在空间尺度上，区域模型中的拟合优度低于至少1个流域的模型拟合优度；在实际应用中，可以选择以∑EI30为因变量的月降雨侵蚀力公式对该区域进行土壤侵蚀评价。

英文摘要：

The simple algorithm of rainfall erosivity is important for USLE/RULSE to evaluate soil erosion in large scale. In this article, the models of monthly rainfall erosivity were built up based on rainfall amount and rainfall time and used to a case study in hilly and gully area of Loess Plateau in Northern Shannxi. The results indicates that the R2 of model decrease generally when independent variables changes from P9 （monthlY rainfall for days with daily rainfall greater than or equal to 9.0 mm） to Pro（monthly rainfall）. The R2 of models with ∑EI1o as dependent variable are almost equal to that with∑EI30 as dependent variable, and the fitting goodness of models with ∑E60I10 as dependent variable are little lower. Considered the scale effects, the R2 of models for flood season are lower than that for some month; and the R2 of models for a region are lower than that for some watershed. If these models are applied, the models with ∑EI30 as dependent variables should be chosen to evaluate soil erosion in the area.