Satellite Snow Cover Change Analysis within the Year of Typical Area in Tianshan Mountains

Using the observation snow cover data from Landsat TM and ETM+ from January 2000 to May 2001,the inter annual temporal and spatial characteristics of snow cover over middle Tianshan mountains are analyzed.Combining with digital elevation model(DEM) data,the distribution of snow cover in different terrain conditions and different altitude per-month are acquired.After analyzing the spatial distribution and temporal variation regulation of snow cover,it comes to a conclusion that the snow cover within year is correlated with altitude,aspect and slope.On the whole,the ratio of snow cover within year increases when the altitude increases and it decreases when the slope increases.The average height of snow cover boundary is high in summer and autumn but low in spring and winter.The difference of snow cover in aspect west and east is obvious in certain times,but the difference is less than that of the aspect north and south.This study provides a scientific support for utilization of water resource and the research of climate and environment in Tianshan Mountains.