Precipitation Change and Its Impact on Eco-environment of Qinghai Plateau for the Last 40 Years

Based on the daily rainfall data of 26 stations in 1961-2002 and the precipitation data of 10 stations in eastern Qinghai province,the climatic variation characteristics of rainfall,rainy days and rain intensity were analyzed.The result showed that there was no obvious change in regional rainfall for that period,but the rainfall in summer season was decreasing and increasing in winter season.Although the rainfall and the rainy days in summer season were decreasing,the rain intensity was increasing.The reason for rainfall decreasing in summer season was mainly the decreasing of rainy days,and that for rainfall increasing in winter season was the increasing of rainy days and the daily mean rainfall in rainy day.With the global warming the rainfall of this region obviously decreases in summer and autumn,and the climatic is turning toward warm and dry.