Seasonal Precipitation and Drought Research in Suining Area in Central Sichuan

Based on the analysis of different time scales of precipitation in the past 50 years using the wavelet analysis method in Suining area with the annual and monthly rainfall data from 1961 to 2010.The paper reveals the multi-time scales characteristic of the precipitation changes in the region,and predicts future precipitation and circulation background and mechanism analysis caused by spring drought and summer drought by using the synoptic principle.It shows that there are obvious periodic oscillation of 3-5a for spring,summer and annual precipatation.Summer precipitation and annual precipitation have the same variation,which infers annual precipitation of 2011~2014 will be less than normal level in Suining area.Drought tends to happen 1 or 2 years after the maximum of wavelet coefficient.If spring cold air and southern branch trough are slightly weaker,severe spring dnceght tends to happen in Suiming area.In the summer,when the West Pacific subtropical high is slightly stronger than normal years and westerlies' position is significantly northward,severe summer drought tends to happen.