祁连山老虎沟12号冰川消融区不同天气条件下的能量收支特征

Characteristics of energy budget under different weather conditions in the ablation area of the Laohugou Glacier No. 12,Qilian Mountains

冰川表面能量平衡模型建立了冰川与大气之间的联系。为探讨不同天气条件对冰川能量收支的影响,利用祁连山老虎沟12号冰川海拔4 550m处的气象资料(2011年8月24日-9月6日),结合能量平衡模型,分析了不同天气条件下的能量收支变化特征。结果表明:受云量影响,晴天条件下向下短波辐射(318.3W·m-2)是多云条件下的1.5倍,是阴天条件下的3倍。三种天气条件下的向下长波辐射,晴天(215.4W·m-2)<多云(267.4W·m-2)<阴天(291.6W·m-2)。受固态降水的影响,阴天条件下冰川反照率(0.50)是晴天时的2倍多。而三种天气下的最大消融耗热,晴天(739.6W·m-2)>多云(582.8W·m-2)>阴天(324.5W·m-2)。在能量收入项中,净短波辐射是主要来源(98%),但是受天气条件影响,能量支出各项所占比例有明显差异;在三种天气条件下,净长波辐射所占比例分别为35%、31%和23%,消融耗热所占比例分别为62%、64%和75%,潜热通量所占比例相差不大。

The connection between the glacier and the atmosphere was established by the energy balance model.Based on the meteorological data from August24 to September6,2011,at the elevation of4 550 m of the Laohugou Glacier No.12 in the Qilian Mountains,the characteristics of energy budget under different weather conditions were analyzed by the energy balance model. It is found that,the downward short wave radiation on fine days(318.3 W·m-2)is about1.5 times as much as that on cloudy days and three times as much as that on overcast days. With the variation of weather conditions from fine to cloudy,the downward long wave radiation shows an increasing trend. Downward long wave radiation in fine days(215.4 W·m-2)< downward long wave radiation in cloudy days(267.4 W·m-2)< downward long wave radiation in overcast days(291.6 W·m-2).Due to the influence of solid precipitation,the glacier albedo in overcast days(0.50)is more than twice as large as in fine days. Maximum ablation heat consumption in fine days(739.6 W·m-2)> maximum ablation heat consumption in cloudy days(582.8 W·m-2)> maximum ablation heat consumption in overcast days(324.5 W·m-2). Net short wave radiation(98%)is the main source of energy income. However,there is significant differences in the proportion of energy output due to weather conditions. Under the three weather conditions,the proportion of net long wave radiation is35%,31% and23%,respectively. The proportion of ablation heat consumption reached62%,64% and75%,respectively. The proportion of latent heat flux varied little.