The Spatial Distribution and Properties of Snow Cover in Binggou Watershed,Qilian Mountains: Measurement and Analysis

The study area is Binggou watershed of the Qilian Mountains,located in Qinghai province,China.In this paper,the snow properties were measured using some advanced instruments in Binggou watershed,and then the temporal and spatial relationships of the properties of snowpack were analyzed.With snow scales,snow forks,handheld loupes with scale,ASD-FR,portable albedometer and so on,the distribution of snow depth,along with other properties such as snow density,snow liquid water content,snow reflectance,snow surface albedo,snow grain size and temperature,were measured during December 2007 and March 2008.In addition,snow profile properties were measured with snow pit work and the snow equivalent density was calculated.Results of snow depth measured from snow scales indicate the spatial distribution of snow depth in alpine is quite various.The snow in shade slopes is much deeper than that in sunny slopes.The liquid water content derived from snow fork is less than 3%.The measured snow spectral reflectance demonstrates firmly that the snow reflectance has a strong dependence on snow grain size,snow type(contamination) and surface roughness.Snow surface albedo was measured using a portable albedometer.The results show that the snow surface albedo varies in dependence of surface liquid water content,except for new snow.Results of the snow pit work reveal various snow vertical structures: fine snow,old snow,ice,coarse grain snow.When the snow depth is more than 20 cm,the snow cover often works like a heat insulation layer.The snow equivalent density varies temporally and spatially in a small extent.The snow equivalent density was calculated to be 0.16 g·cm-3.