天山北坡积雪期不同下垫面雪密度及液态含水率对比分析

Comparative analysis of snow density and moisture content of heterogeneous surface in the snow period of the north slope of Tianshan Mountain

利用Snow Fork雪特性分析仪和超声波雪深传感器,分别对林地、草地和灌木地的积雪深度、雪密度及液态含水率进行监测,对比分析3种下垫面雪密度、液态含水率在积雪垂直剖面分布的差异性及积雪深度随时间累积的变化特征。结果表明:主要积雪期为历年11月至次年2月,积雪期3种下垫面雪深变化规律基本一致,呈累积变化趋势,但林地因自身树冠层的截留作用,其平均积雪深度最小,较林外草地积雪总量,林地树冠层对降雪的截留量约为45.33%;积雪初期(10月底至11月中旬)各下垫面雪密度、液态含水率从积雪底层至表层变化趋势基本一致,最大值均出现在积雪表层或中间层;积雪后期(12月至次年2月中旬)3种下垫面雪密度峰值均出现在积雪底层,而液态含水率存在差异性,林地、草地液态含水率在积雪底层0cm-10cm处达到峰值,灌木地在中间层20cm-30cm处达到峰值;不同下垫面在同一积雪层处雪密度、液态含水率随时间累积均呈递增趋势。

The Snow Fork and ultrasonic snow depth sensor were used to monitor the daily variations of snow depth and the changes in snow density and liquid water content of layered snow on three different underlying surfaces of forest land, grassland and shrub land. Distribution of snow density and liquid water content on the three kinds of underlying surface in the vertical profile, and the cumulative characteristics of accumulated snow depth over time were compared. The results show that the main snow cover period on the northern slope of the Tianshan Mountains is from November to February next year. The snow depth changes for the three kinds of underlying surfaces are identification. The average snow depth of the forest land is the smallest, and the total snow cover is greater than the grass outside the forest. Quantity, the canopy interception of forest canopy is about 45.33%. At the initial stage of snow(October to the middle of November), the snow density and liquid water content for the three kinds of underlying surface are identification which are change from the snow-covered bottom layer to the surface layer, and the maximum value appears in the surface layer or middle layer of the snow. In the late snow cover period(December to mid-February), the peak snow density of the three underlying surfaces appears on the bottom of the snow. The liquid water content peaks in the snow layer of forest land and grassland are 0 cm-10 cm in the snow bottom layer, while the liquid water content in the shrub layer were 20 cm-30 cm in the middle of snow cover. The liquid moisture content and snow density of the woodland at the snow bottom are greater than grassland and shrub lands.