中文摘要：

积雪消融是北方地表重要的水文过程，与森林植被有着极其紧密的关系。以祁连山大野口流域不同海拔梯度下青海云杉林内积雪为研究对象，在积雪消融期选择典型样地作为观测点，通过野外实测降雪量、积雪厚度、空气温度、土壤温度、郁闭度等观测指标，系统研究了积雪消融与温度、海拔高度和郁闭度等之间的关系。结果表明：1）积雪消融主要发生在10月到翌年4月，并随青海云杉林内温度和土壤温度先降低后增大，积雪消融速率呈“V”字形变化模式，在1月最小，不同海拔高度平均为0．51mm·d^-1。2）积雪密度、降雪量、积雪厚度和雪水当量都随海拔的升高而呈现递增的趋势，积雪厚度与雪水当量、郁闭度、差异极显著（P〈0．01），与降雪量差异显著（P〈0．05）。3）在同一海拔不同坡位的青海云杉林，积雪厚度大小为下坡〉上坡〉中坡，雪消融速率为下坡〉中坡〉上坡；不同坡向，积雪消融速率为半阳坡〉半阴坡〉阴坡。4）2700m林缘和林内的积雪消融速率都呈现先减后增的变化趋势，1月份消融速率最小，林缘积雪消融值为1．35mm·d^-1，林内积雪消融值为1．22mm·d^-1；4月份消融速率最大，林缘消融值为12．03mm·d^-1，林内消融值为9．01mm·d^-1。

英文摘要：

Snowmelt is an important hydrological process in northern China, which has very close relationship with forest vegetation. Snows occurred in Qinghai spruce forest under different elevations in the Dayekou basin of the Qilian Mountains were taken as research object,the typical sampling sites were chosen as the observation points during the snowmelt period. Indices such as snowfall, snow thickness, air temperature, soil temperature, and canopy density were measured in these sites. The relationship between snowmelt and temperature, altitude and canopy density was systematically studied. The results indicated that 1） snowmelt occurred during October to April of next year. The rate of snowmelt decreased and then increased with forest interior temperature and soil temperature, showing a ＂V-type＂ curve. The minimum rate occurred in January （0.51 mm·d^-1）. 2） Snow density,snowfall,snow cover thickness and snow water equivalent were all progressively increased with the increase of elevation. Very significant differences were found between the thickness of the snow cover and the factors such as snow water equivalent and canopy density （P〈0. 01）. Differences between the thickness and snowfall were significant （P〈0.05）. 3） The rank of snow cover thickness at the same elevation but different slope positions was down-slope 〉 up-slope mid-slope. The rank of snowmelt rate at the same elevation but different slope positions was down-slope 〉 mid-slope 〉 up-slope. 4） The snowmelt rate in inferior forest and edge 2 700 m above the sea level decreased first and then increased,and the minimum rate occurred in January. 1.35 mm·d^-1 for forest edge and 1.22 mm·d^-1 for the inferior forest. The maximum rates were found in April= 12.03 mm·d^-1 for the forest edge and 9.01 mm ·d^-1 for the inferior forest.