Analysis on the Characteristics of Usable Precipitation in Sichuan

Using 40a ground observational data from 143 meteorological stations in Sichuan, this study addresses the characteristics of usable precipitation of Sichuan. The results show that water resources in Sichuan area obviously seasonal change, precipitation and evaporation are highly concentrated in summer, while winter has least precipitation and evaporation. Annual usable precipitation coefficient is 0. 45, like precipitation and evaporation characteristics, the usable precipitation coefficient in winter is the smallest, largest in summer, and the usable precipitation coefficient in autumn is higher than it in spring. There is a normal distribution of usable precipitation coefficient in a year, increasing from January to July and reducing from August to December gradually. In general, the distribution of usable precipitation coefficient in Sichuan is uneven, the usable precipitation coefficient in Sichuan Basin is lower than it in the Western Plateau and Panxi area.