藏北羌塘高原双湖地表热源强度及地表水热平衡

青藏高原加热及地—气间物质能量交换对我国、东亚乃至全球的天气和气候系统都有着非常重要的作用,受客观条件限制,藏北羌塘高原腹地尚无系统的地—气相互作用过程观测。本文利用中国科学院羌塘双湖极端环境综合观测研究站2011年10月-2012年9月一年的自动气象站观测数据,分析了年内季节和日尺度下双湖地区地面加热场特征,探讨了地表能量平衡及水量平衡特征,结果表明：(1) 双湖地区年内地表热源强度基本为正,年平均热源强度为79.5 W/m²;然而地表热源强度呈现明显的季节和日变化规律,夏季热源强度大于冬季,白天热源强度大于夜间。夏季地表白天为强热源,夜间为弱热源,冬季地表白天为强热源,夜间为冷源。(2) 双湖地区地表能量分配季节变化明显,7、8月份地—气间主要以潜热交换为主,其他月份主要以感热方式进行热量交换,年平均上主要以感热交换为主,年均感热通量和潜热通量分别为55.4 W/m²和24.1 W/m²,波文比为2.3。(3) 双湖地区降水和蒸发皆主要集中在6-9月,年降雨量为332 mm,年蒸发量为312.9 mm,年水量差为19.1 mm,地表水量存在不平衡现象。(4) 双湖地区地表蒸发力很强,年潜在蒸发为1888.2 mm,年均湿润指数为0.17,属典型半干旱气候特征。

Surface heat source intensity and surface water/energy balance in Shuanghu,northern Tibetan Plateau

Heat and energy exchange between land and atmosphere over the Tibetan Plateau is of great importance for the climatic system in China, east Asia as well as the world. However, there is no systematic observation on atmosphere-land interaction in northern Tibetan Plateau due to rough environmental conditions. In this paper, surface heating and energy/water balance within various temporal scales are analyzed from October 2011 to September 2012 in Shuanghu region. The results show that: (1) the surface heating is positive in the whole year, with an average value of 79.5 W/m². However, the intensity displays obviously seasonal and diurnal patterns in this region, where it is stronger in summer than that in winter, and also higher in daytime than at night; (2) Surface energy condition varies seasonally, and latent heat exchange is dominated in July and August; (3) surface moisture imbalance occurs in this region, where the annual rainfall and evaporation is 332 mm and 312.9 mm respectively, and the difference is 19.1 mm. (4) The evaporative potential is strong with a humid index of 0.17, belonging to a typically semi-arid climatic region.