中文摘要：

利用青藏高原及其周边的97个气象台站1961-2000年的逐月降水量资料,以Mann-Kendall趋势检验方法结合主成分分析,分析了高原降水量40年来的时间变化趋势和空间演变特征,并探讨了其变化趋势的区域分异因素和可能的趋势突变时间。结果发现,高原站点40年年降水量大部分表现为增大趋势,只有青海东南部和南疆及西藏部分站点出现减小趋势,这一时间变化趋势的空间分布则大致表现为高原中东部和南北的反向变化,同时高原站点冷季降水量增大趋势明显;以冷、暖季降水量的第三载荷向量场分异进行的分区在10年年代际和逐年变化中都有明显体现,暖季区域分异因素的主要相关区域降水量变化趋势与相应载荷向量的时间变化相关显著,在1989年出现可信的突变时间点;冷季相关分异区域的降水量变化趋势在1987年出现明显增大趋势,同样与载荷向量的时间变化相关显著,但突变时间点检测不明显。

英文摘要：

The monthly precipitation data from 97 stations over Qinghai-Tibet Plateau from 1961 to 2000 are analyzed by using the Mann-Kendall test and the principal component analysis methods. The spatial-temporal variability characteristics of precipitation during last four decades are briefly described, and the abrupt of the further factors of the distribution in spatial and the variation trends of abrupt changes are discussed. The results indicate that the precipitation of most stations over Qinghai-Tibet Plateau shows an increasing trend, while the decreasing trend appears in some stations in southeast of Qinghai and the stations scattered in Tibet. There is an opposite-phase spatial relation between the variation trend of precipitation in the middle and east of Plateau and that in the south and north. At the same time there is an obviously increasing trend in of precipitation in the cool season. According to the spatial distribution of the third loading eigenvectors （TEE） of precipitation in cool and warm seasons, the regions classified （RC） are reflected in spatiality between the interdecadal and interannual variations. Corresponding to the RC the variation trends in precipitation in warm season have an obvious relationship with the TLE in temporal variation, with their abrupt changes detected in 1989, without the detection of the abrupt changes in the same situation in cool season.