中文摘要：

利用三峡库区大宁河流域及其周边共21个雨量站8a的日降雨量资料，按照日降雨量侵蚀力模型，在地理信息系统软件ArcGIS9．0支持下，分析了该流域降雨侵蚀力的时空分布特征。研究表明，该流域年均降雨侵蚀力R值在空间分布上与流域高程变化一致。随着流域高程变化，侵蚀力R值呈现上游迅速降低，中游平缓到下游增大的趋势，最高和最低侵蚀力R值分别位于流域西北部的高楼站附近和西南部的福田站附近；降雨侵蚀力R值的年际分配差异明显，最大年R值为最小年R值的2．16倍；降雨侵蚀力R值的季节分布呈单峰型，集中程度高，5—9月上半月占全年的90．4％，全年R值的高峰出现于7月份和8月份上半月，占全年的38．8％。

英文摘要：

With the aid of the rainfall erosivity model using daily rainfall and geographic information system （GIS） software, ArcGIS 9.0,daily rainfall data from 21 weather stations in Da＇ning River watershed and its adjacent area, the Three Gorges Reservoir Region, were used to analyze the temporal-spatial variations of rainfall erosivity（R factor） for the watershed. R factor varied consistently with watershed elevation. R factor decreased rapidly in the upper reaches of the watershed from Gaolou station to Wuxi station, trended towards gentleness in the middle reaches from Wuxi station to Dachang station, and increased gradually in the down reaches from Dachang station to Wushang station（watershed outlet）. There was a great variation in year-toyear R factor with the maximum being three times greater than the minimum. The distribution of rainfall erosivity was highly seasonal with a single peak. Summer months from May to early September typically contributed 90.4% of the yearly R factor. July and early August were the peak months with more than 38% of the yearly R factor.