蒸散发是地表能量平衡的关键环节，准确估计流域蒸散发对水资源管理、作物估产、以及环境保护等具有重要意义。研究结合中国中高纬度区域气候特征、土地利用类型以及植被动态特征，改进了基于地表能量平衡系统（Surface Energy Balance System，SEBS）的蒸散发估算模型。以松花江流域为例，进行大尺度流域的多年蒸散发反演。通过多年流域水量平衡、流域内生态观测实验以及全球通量观测网络评价数据验证模型估算精度，同时借助陆面过程模型和NASA的MOD16蒸散发产品进行交叉验证，评估模型模拟精度。结果表明，改进的SEBS模型在全国范围内精度并不统一，但在松花江、辽河流域估算精度较高，因此基于地表能量平衡的蒸散发估算模型是一种估算我国中高纬度区域蒸散发的可行方法。松花江流域时空变化研究发现，流域多年蒸散发总值变化不大，但存在空间上的变异性。

Evapotranspiration (ET) is the key link between land surface energy balance and water movement.Accurate estimation of ET on basin scale is of great significance to climate change studies,water resources management,crop yield estimation and environmental protection.Combining the climate characteristics,land use types and vegetation dynamics in the middle and high latitudes of China,an ET estimation model was proposed based on Surface Energy Balance System (SEBS)..The model was then applied to the Songhua River basin to estimate ET.The estimation accuracy of the model was validated by the water balance and ecological observations in the basin,and MTE data of global flux observation network.The simulation accuracy of the model was also evaluated by cross-validation of a land surface process model and NASA MOD16 ET .The results show that the improved SEBS model has a high accuracy in estimating the ET in Songhua River and Liaohe River basins in China,but the accuracy is not uniform in the whole country;The model is a reasonable method for estimating the ET in the middle and high latitudes of China;The spatial and temporal changes of the Songhua River basin show that the total ET in the basin has been relatively stable in recent years,but with a spatial variation.

黑龙江省自然科学基金（E20180006）；国家自然科学基金（41401042）；教育部人文社会科学研究项目（19YJCZH228）