Spatial and Temporal Characteristics of Precipitation Resource in Southwest China during 1961-2000
我国西南地区1960～2000年降水资源变化的时空特征

On the basis of the monthly precipitation data for the period 1961-2000 collected from 96 observational stations in Southwest China (SWC),the methods of principal component analysis, rotated principal component analysis,and wavelet analysis are used to analyze the spatial and temporal characteristics of annual precipitation resource.The main results show that the yearly precipitation resource in the western part of SWC increased in these 40 years,and the yearly precipitation resource decreased in most eastern areas except Chongqing.The spatial characteristics of precipitation resource in Southwest China are complex with anomaly differencebetween the south and the west,and in the east and the west of SWC.The precipitation resource abnormal area can be divided into eight subregions:southern Yunnan,western Sichuan Plateau, eastern Yunnan and western Guizhou,eastern part of Sichuan Basin,western part of Sichuan Basin,western Yunnan,northeastern Guizhou and southeastern Chongqing,and Liangshan mountain. The precipitation in the plateau of western part of SWC had a dry-wet-dry process and an increasing trend in 1990s.The precipitation in eastern part of Sichuan Basin had a wet-dry-wet process.The precipitation appeared a decreasing trend in western part of Sichuan Basin and entire southeastern part of SWC.Except the remarkable period of 14 years in the regions of western Sichuan Plateau,southern Yunnan,eastern Yunnan and western Guizhou,the main periodic and annual change laws of other regions are different from each other.