The Spatial-temporal Distribution and Change Characteristics of Precipitation-phase in Sichuan

Using the reorganization observed data from 156 national stations during 1981 ~ 2013 in Sichuan Province,statistical analysis the annual mean and monthly mean characteristics of rain day,snow day and sleet day,and the rain- snow transition condition. Using linear- trend method,Mann- Kendall test,quantitative analysis the spatial- temporal distribution and climate change characteristics of precipitation- phase in Sichuan. The results show that:(1) the annual mean snow day and sleet day show the distribution of “west more and east less”,the annual mean rain day show “east more and west less”;(2) the mean rain- snow transition days in the middle and southern of Basin is 0. 1 ~ 2,the days in the Western hills is 3 ~ 5,the days in the west Sichuan highland is more than 10,there is no rain- snow transition in Panzhihua,the days in Liangshan show " west less and east more";(3) from the linear- trend method,Mann- Kendall test,we find that the days of different phase precipitation is decreasing,the Sichuan Province in drying.