融雪期中国天山西部山地表层积雪能量收支特征

Energy Budget of Near-Surface Snow during Snowmelt Period in the Western Tianshan Mountains,China

表层积雪的能量收支特征对积雪物理特性变化和融雪等过程具有重要影响。本研究利用2010年融雪期在中国科学院天山积雪雪崩研究站内的雪层密度、含水率、雪层温度以及热通量等观测数据,分析在距雪表40 cm范围内雪层能量收支的时空变化特征。结果表明:表层积雪的能量交换主要发生在距雪表20 cm范围内,短波穿透辐射是表层积雪最重要的能量来源。热传导、短波穿透辐射和潜热均随时间逐渐增加。在过渡期和融雪前期,表层积雪的平均总能量为负,融雪主要发生在积雪表层。由于夜晚潜热影响使得融雪后期表层积雪总能量为正值。融雪能影响整个雪层。

Energy buget near the surface snow have great influences on the variations of the snow physical characteristics and snow melt process. The snow density, liquid water content, snow temperature and heat flux were measured at the Tianshan Station for Snow Cover and Avalanche Research, Chinese Academy of Sciences during the snowmeh period in 2010. This study analyzed the temporal and spatial variations in the energy budget of near-surface snow during different snowmelt periods. The results indicated that the heat conduction generally occurred in the 20 cm deep snow from the surface. The penetration of shortwave radiation was the most important external energy source. Heat conduction, penetration of shortwave radiation and latent heat flux were increased with the snowmeh periods. In the transitional period and pre-snowmelt periods, the daily average total energy in the near-surface snow was negative, snow melt mainly occurred in this layer. The daily average total energy was positive, due to the influence of latent heat at night. Thus, the snow meh can influenced all the layers.