青藏高原湖泊分布密集，较少受到人类活动的影响，是研究气候变化与水循环过程的理想地区。由于气象观测站点较少，特别是湖泊主要分布的内流区，同时卫星降水产品存在较大的不确定性，这大大限制了对青藏高原湖泊水量平衡的理解。本项目提出使用30m的SRTM-DEM数据，建立湖面高程与面积的关系，使用基于Landsat和Sentinel-2的湖泊面积，估算面积大于1平方公里湖泊的水位变化，从而获得湖泊水量变化。同时，联合高分辨率的TerraSAR-X/TanDEM-X和SRTM数据，使用DInSAR处理技术，对湖盆内冰川厚度变化进行计算，进而估算冰储量变化。结合2000-2018年湖泊水量与冰量变化，分析冰川分布率不同的湖盆之间湖泊变化差异，定量评估冰川融水对湖泊水量变化的贡献。此研究的开展，对量化湖泊水量平衡中冰川融水影响、提升青藏高原湖泊变化对气候与冰冻圈变化响应机制的理解都具有重要的科学意义。

There is dense distribution of lakes in the Tibetan Plateau (TP). These lakes are sensitive indicators of climate changes as few direct human activities there. At present, the understanding of lake water balance is poor because limited weather stations as well as large uncertainties of satellite-based precipitation products, especially in the Inner TP with more than 70% lakes’ number and area. In this project, we propose to construct the correlation between lake area and elevation using SRTM DEM (30 m pixel size). The lake area derived from Landsat and Sentinel-2 is input into the correlation to deduce the corresponding lake elevation. Combining the lake area and elevation changes, the lake volume changes are estimated. In addition, we combine TerraSAR-X/TanDEM-X and SRTM to calculate the changes of glacier thickness at lake-basin scale using DInSAR technologies. Furthermore, the glacier mass balance is estimated with glacier density. The differences of lake area, level and volume change in basins with different glacier coverage, and the contribution of glacier melting to lake water balance can be quantitatively evaluated. The execution of this project will improve our understanding of lake water balance, response mechanism of increasing lake water storage on the TP to climate and cryosphere changes.