Changing characteristics of different intensities of snowfall in Altay region,Xinjiang

based on the daily snowfall data of 7 stations in Altay from 1961 to 2010,using the linear trend and sixth- order polynomial we analyzed the climate features of different levels of snowfalls. The result shows that winter snowfall of the area decreased from northeast to southwest; the maximum occured in Aletay station and minimum in Fuhai station; the spatial distribution of light snow percentage decreased from northeast to southwest, moderate snowfall did not change much,heavy snow and blizzard consistented with the distribution of winter snowfall; heavy snow and blizzard in Aletay,Fuyun,Qinghe stations were much larger than the rest of stations. The total number of snow days were decreasing from west to east,as well as all levels. The intensity of snow was increasing,mainly reflected in increase of the intensity of light snow and blizzard; the intensity of little snow, heavy snow and blizzard were the weakest in 1970s,and the strongest in 2000s.