Abstract: The variations of snow cover depth and snow cover duration in the Xilin River Basin,Inner Mongolia were studied using the 35 year (from 1981 to 2016) daily meteorological data (precipitation,temperature,etc.) and the daily snow cover depth data from the Xilinhot,Abagachi,Linxi and Hexigten Banner meteorological stations.The relationships among the climate factors and the snow cover depth and snow cover duration were analyzed.Results indicated that both the snow cover depth and snow cover duration were in a slight increase trend.There were the turning points of both the snow cover depth and snow cover duration,the mutation of average annual snow cover depth occurred in 1984,but there was no significant mutation of snow cover duration.Furthermore,the change cycles of snow cover depth and snow cover duration were 10-30 years and 12-30 years respectively.There were the significant negative correlation between the snow cover depth and snow cover duration and the climate factors,such as temperature,average wind speed,sunshine duration and effective accumulated temperature in snow cover season.However,there were the significant positive correlations among the snow cover depth,snow cover duration and relative humidity.Path analysis indicated that the effect of temperature on snow cove variation was more remarkable than that of other climate factors no matter directly or indirectly.It is very import to study the variation of snow cover and its response to climate change in cold and arid areas for water resources management,agricultural development and disaster prevention and control in grassland drainage basin.

Key words: snow cover depth, snow cover duration, climate factor, path analysis, Inner Mongolia, Xilin River Basin