祁连山老虎沟流域春季积雪属性的分布及变化特征

利用祁连山老虎沟流域布设的花杆观测了该区春季积雪的属性(深度、 表面反射率、 密度及含水量、 粒径), 并结合自动气象站上的积雪深度和反照率数据, 对研究区春季积雪属性的分布及变化特征进行了观测和分析. 结果表明: 流域内积雪分布很不均一, 在阴坡雪深大, 阳坡雪深小; 在不同海拔上, 雪深随海拔有增高的趋势; 不同类型、 不同表面粗糙度、 不同密度、 不同含水率的积雪反射率不同, 不同地物的反射率也不同; 积雪剖面中逆温层结的形成与表面温度、 雪深有密切关系, 在一天内新降雪的密度及含水率随时间的变化具有较好的一致性.

Distribution and Variation of Spring Snow Cover in Laohugou Watershed of the Qilian Mountains

In order to understand the physical process of snow cover and its feedback to climate system, it is necessary to study the properties of snow cover. In this paper, the distribution and variation of snow cover in spring in Laohugou watershed of the Qilian Mountains was investigated. The snow cover properties, i.e., snow depth, snow density, snow liquid water content, snow reflectance, snow surface albedo, snow grain size and temperature, were measured using some advanced instruments during the observation. In addition, snow cover profile was measured in snow pits. Snow cover depth measurement found that the spatial distribution of snow cover depth is quite various. The snow cover in shaded area is deeper than that on other slopes. The measured snow spectral reflectance shows a distinct dependence on snow grain size, snow type, snow depth, snow density, snow liquid water content and surface roughness. Snow surface albedo was measured by automatic weather station. When snow depth reaches a certain value, the snow cover always has heat preservation effect. There was a temperature profile with a temperature inversion layer depending on snow cover depth and surface temperature. Within a day, new snow density variation is consistent with water content variation.