近35a锡林河流域积雪变化及其对气候的响应

Variation of Snow Cover and Its Response to Climate Change in the Xilin River Basin in Recent 35 Years

利用锡林浩特站及周边阿巴嘎旗、林西和克什克腾旗气象站1981—2016年逐日气象数据（降水量、气温等）、逐日雪深数据,分析了锡林河流域近35 a雪深、积雪日数的变化特征,以及气象因子与雪深、积雪日数之间的相关性。结果表明：近35 a来锡林河流域年平均雪深及年平均积雪日数在时间序列变化均呈微弱的上升趋势。在时间转折上,年平均雪深在1984年发生突变,而年积雪日数并没有发生明显的突变。从周期变化来看,年平均积雪10~30 a的周期变化最明显,而年平均积雪日数在12~30 a的时间尺度上的周期变化最为明显。研究区气象因子与积雪的相关性表明,雪深、积雪日数与气温、平均风速、日照时数、〉0℃有效积温在整个积雪期均呈极显著的负相关关系,而相对湿度与积雪深度及积雪日数变化之间呈极显著的正相关。运用通径分析发现,气温对积雪变化的影响,无论是通过直接作用,还是通过间接作用,均大于其它因素的影响。由此可见,相比其它气象因子,积雪对气温的变化更加敏感。研究积雪动态变化及其对气象因子的响应对寒旱区草原合理利用水资源、农牧业发展和灾害防御具有重要的现实意义。

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.