Changes of precipitation spatial-temporal over the Qinghai-Tibet Plateau during last 40 years

The rmnthly 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 rmst stations over Qinghai-Tibet Plateau shows an increasing trend,while the decreasing trend appears in some stations in southeast of qnghai 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 sewn.According to the spatial distribution of the third loading eigenvectors (TLE) of precipitation in cool and warm seasons,the regions classified (RC) are reflected in spatiality between the interdecadal and interannual variations.Cbrresponding 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.