中文摘要：

根据青海省德令哈地区海拔3500--4000m左右的祁连圆柏树木年轮资料重建的该地区公元1000年以来的年降水量变化，使用滑动t检验和滑动F检验等气候突变检测方法对千年降水量30年气候均值和均方差的突变进行了分析，探讨了气候突变的可能原因。研究发现．德令哈地区千年来降水量的30年气候均值和均方差发生了多次显著突变．其中均值突变14次、均方差突变8次；太阳活动极小期内的降水量与其前后同时段内降水量的均值相比存在显著差异；降水量突变发生的时间和方向与太阳活动异常较为一致．因此推测太阳活动的长期变化是导致德令哈降水量发生突变的主要原因。近一个多世纪以来．德令哈地区的降水量突变与东亚夏季风的年代际变化有密切联系。德令哈降水量发生突变的时间与我国东部地区相比具有一定的超前性，对预测降水量的长期变化趋势具有重要的指示作用．

英文摘要：

Based on the tree ring width chronologies developed in Delingha region, Qinghai province, the annual precipitation variations for the last 1000 years has been reconstructed recently. In this study, we investigate the abrupt changes of precipitation for the last 1000 years. Smoothing t-test and smoothing F-test methods were used to search for possible abrupt changes in the mean value and the standard deviations of 30-year climatic average precipitation. Significant abrupt changes were found during the last 1000 years and we suggested that solar activity played an important role in influencing these changes. It is evident that the precipitation decreased significantly during the periods of the Wolf, Spoerer, Maunder and Dalton minima of solar activity, and the t-test verified the existence of statistically significant differences within these periods. The time and the direction of abrupt changes of precipitation coincided well with the abnormal variations of solar activity. The abrupt changes of precipitation in Delingha may link with the interdecadal changes of East Asian Summer Monsoon for the last century. The time of abrupt changes in Delingha was ahead the time of abrupt changes in eastern China, which may be an important indicator for long-term change forecast of precipitation.