Analysis of Precipitation Change in North Xichang in Recent 40 Years

Based on the daily precipitation data of north Xichang from 1974 to 2009,annual days of levels precipitation data are analyzed by current extreme climate index.And then the variation characters of precipitation events are diagnosed using the least squares method,moving average method,polynomial fitting method and Morlet Wavelet method.The results show that annual days of rain date and hail decreased significantly.Total precipitation,annual maximum daily precipitation,heavy precipitation days R95%,moderate precipitation days R75%,and total precipitation during the rainy season are rising,but not significantly.The downward trend of snow days is not significant,too.rainstorm days in long-term trend is not obvious.There are certain types of precipitation events or extreme weather oscillation cycle.For climate change at this stage,we proposed deal recommendations.