The band characteristics of long-term variation of precipitation and water resources in east asia monsoon region

In this paper, by means of the “CWH” (circulation-weather and climate-agricultural harvest) analytical method, drawing from the monthly mean long-term data of the global sea level pressure field and annual precipitation data and grain yield data of some regions in East Asia, the time-space characters of low-frequency fluctuation of East Asian precipitation with band distribution are analyzed. It is revealed that the band of 20–30 years quasi-periodic fluctuation is located in Southeast Asia and the coastal areas of South China. Moving forward to west and north, the period of fluctuation of precipitation tends to become longer, both bands with about 40-yr and 60–80-yr quasi-periodic fluctuation are respectively situated in the middle-lower reaches of the Yangtze River and North or Southwest China. Furthermore, the relationships between the fluctuations of precipitation bands and large-scale circulations are analyzed. The relationships between precipitation and types of water resources are discussed as well. In addition, the tendency of long-term variation in rainfall is predicted.