乌鲁木齐河流域季节积雪的基本特征

Characteristics of Seasonal Snow Cover in Urumqi River Basin

乌鲁木齐河流域的季节积雪受气温、降水量、水汽来向、山坡朝向、海拔和下垫面性质所控制和影响,具有明显的空间变化规律。按积雪期的长短,可划分为瞬时积雪、不稳定积雪、稳定积雪和永久积雪。气温低、雪层薄、雪层内温度梯度大,积雪密度小,雪面蒸发强是其特征。

The seasonal snow cover in Urumqi River Basin varies temperally, influenced by air temperature, precipitation, moisture source, slope direction, elevation and ground surface condition. Snow cover is divided, by its duration, into four classes as the new snow, short term snow cover, long term snow cover and permenent snow cover. The snow cover is characterized by shallow snowpack, less snow density and high evaporation rate in the winter.