Influence factors of snow change in Lake Bosten Basin

Abstract

积雪是西北干旱地区河流的主要补给源,是绿洲的生命线.积雪的时空变化是全球变化的区域响应敏感因子之一,同时也是影响西北干旱地区地表水资源变化的主要因子之一.本研究利用MODIS雪盖产品、地表温度、SSM/I雪深、DEM等数据,通过GIS空间分析及地统计分析功能,系统分析了博斯腾湖流域雪盖、雪深的时空变化规律及其与影响因素之间的关系.研究表明,研究区雪深和雪盖多年月平均值从8月份到1月份达到最大值,到7月份降到最低值.但月最大雪深却出现在3月份.雪盖、雪深与地温相关系数分别达到-0.878、-0.853,与分布高程均值相关系数分别达到-0.626和-0.791.雪深最大值受海拔影响有明显的陡坎效应.从12月到8月份随着时间的推移雪的深度在降低,陡坎向高海拔方向移动.9-11月份雪深在加深,陡坎向低海拔方向移动.同一高程段雪深的变幅反应坡向对雪深的影响,变幅越宽坡向影响越大.并且变幅也有先从低海拔到高海拔移动,然后再回到低海拔的特点.本研究对了解该研究区积雪特性的研究有很大作用,可为在该地区开展融雪径流模拟等研究提供重要的参考信息.;Snow is the major water source of rivers in the arid areas in the northwest. Its temporal and spatial variation is one of the sensitive factors responses to global change in the lake. This paper, using MODIS Snow Cover, Surface Temperature, SSM/I Snow Depth, DEM and other data with the help of spatial and statistics analysis function of GIS, analyzes the temporal and spatial variation regularity of snow cover and snow depth of Lake Bosten Basin, and studies their relationships with the influencing factors. The results show that monthly average of snow cover and snow depth start to rise from August, reach a maximum until January, and then decline to a minimum in July, while the maximum snow depth appears in March. The correlation coefficients of snow cover, snow depth and surface temperature, are -0.878 and -0.853, respectively, while the coefficients are -0.626 and -0.791 between snow cover, snow depth and elevation. The maximum snow depth is significantly affected by the altitude with a steep step effect. From December to August, the snow depth is reducing with time, and the steep step is moving towards the high altitude, while the situation is totally opposite from September to November. The snow depth amplitude of one segment elevation response to the impact of aspect on snow depth, and the influence is greater while the amplitude is wider. Simultaneously, the amplitude, as a characteristic, moves from low altitude to high and then to low again. This study plays an important role in understanding characteristics of snow in Lake Bosten Basin. It will also provide important references for other studies, such as the simulation of snowmelt runoff.