复杂地形区地表蒸散量遥感反演研究——以海河流域为例

复杂地形区地表蒸散量的估算是水文学相关领域研究的热点与难点之一。近年来海河流域山区植被覆盖增加迅速，植被变化引起的水循环变化对于流域水资源的形成至关重要，准确估算山区蒸散耗水对于科学评估该区域水文循环变化以及对水资源的影响意义重大。然而，海河流域山区地形复杂，观测资料稀少，如何准确估算山区蒸散成为该区域水文研究和水资源管理必须解决的技术瓶颈。因此，本项目以海河流域为例，基于遥感数据、气象数据与地形数据改进复杂地形区关键陆面参数的估算方法，实现地形对地表辐射通量、热通量的再分配，建立既简单实用又能刻画复杂地形区地表通量过程主要特征的蒸散发模型，并通过优化时间尺度扩展方法反演过去30年海河流域地表蒸散时空分布，探究复杂地形下地表蒸散量的关键影响因素。研究结果可为复杂地形区径流的预测和水资源的合理利用提供理论指导，并为海河流域日益短缺的水资源问题提供决策依据。

Estimation of surface evapotranspiration in complex terrain is one of the hot and difficult issues in hydrology. Vegetation fraction cover on the mountainous area has increased rapidly in Haihe river basin in recent years. Water cycle change in the mountainous areas caused by vegetation change is of great importance to the formation of water resources in the basin. Estimate evapotranspiration accurately in the mountainous area is of great significance for scientific evaluation of the change in water cycle and the impact on water resources in this region. However, the mountainous area of the Haihe River Basin is characterized by complex terrain and scarce observation data. How to accurately estimate the evapotranspiration in the mountainous area has become a technical bottleneck that must be solved for hydrological research and water resources management in this region. Therefore, this project aims to take the Haihe River Basin as an example, improve the estimation method of the key parameters in complex terrain based on remote sensing data, meteorological data and topographic data, realize the redistribution of surface radiation flux and heat flux by terrain, establish a simple and practical evapotranspiration model that can describe the main characteristics of surface flux process in complex terrain, and obtain the spatial and temporal distribution of evapotranspiration in the Haihe River Basin in the past 30 years by optimizing temporal extrapolation methods, and explore the key influencing factors of surface evapotranspiration in complex terrain. The results can provide theoretical guidance for the prediction of runoff and rational utilization of water resources in complex terrain, and provide decision-making basis for the problem of water resources shortage in Haihe River Basin.