中文摘要：

利用黄土高原及其附近地区99个站点逐日降水观测资料，分析了1956～2005年黄土高原年降水量、侵蚀性降水量、暴雨量的变化趋势和空间特征。研究表明：1956—2005年黄土高原降水在波动中呈现下降趋势，尤其自1980年年以来，降水减少趋势显著。黄土高原地区降水变化具有显著的空间差异，降水偏少最为显著区域位于黄河中游的河口-龙门区间，尤以无定河流域、汾河流域和山西中北部最为典型，年降水量和侵蚀性降水偏少10％以上。存在从北向南沿朔州-离石-临汾一三门峡一带的暴雨异常偏少地带，偏少在20％以上。

英文摘要：

In this study, the spatio-temporal variations of annual precipitation, erosive precipitation and rainstorm over the Loess Plateau were investigated on the basis of the observed data of daily precipitation at 99 stations for the period 1956 -2005. The annual precipitation showed a decreasing trend over the Loess Plateau in the past 50 years. The significant decreasing region mainly appeared in the middle Huanghe （Yellow） River, especially in the Wuding River basin, the Fenhe River basin and the northern and central Shanxi Province, where the annual precipitation and erosive precipitation decreased more than 10%. Rainstorm variation showed a notable spatio-temporal difference in the Loess Plateau and an decreasing zone range from Shuozhou, Lishi, Linfen to Sanmenxia, where rainstorm have descended more than 20%. In the past 20 years, the annual precipitation had a significant decreasing trend over the loess Plateau, whereas the decreasing of erosive precipitation was more intensive than annual precipitation variations and rainstorm changes more intensively than the erosive precipitation.