Variations in lake water storage over Inner Mongolia during recent three decades based on multi-mission satellites

Lake shrinkage is a frequent water resource problem in arid and semi-arid regions that can affect the hydrological cycle and damage the local aquatic environment. Since the 1990 s, many lakes in Inner Mongolia have shrunk significantly. However, the causes of the shrinkage and long-term storage trends of lakes in Inner Mongolia are still poorly understood. Using observations from multi-mission satellites, we analyzed water storage changes in six major lakes in Inner Mongolia over the past 30 years and explored the underlying causes. The results reveal divergent changes between the two lake categories. For each of the tectonic lakes (including Lake Hulun, Lake Dalinuoer, Lake Daihai, and Lake Hongjiannao), the water storage has continuously decreased with annual rates of 0.067 km3/yr, 0.012 km3/yr, 0.021 km3/yr, and 0.01 km3/yr, respectively. In contrast, for oxbow lakes (including Lake Hasuhai and Lake Wuliangsuhai), the storage trends were insignificant (0.001 km3/yr for both). Human activities were the most significant driving factors, especially coal mining, agricultural irrigation, and grazing, which explained more than 70% of the storage changes in Lake Hulun, Lake Dalinuoer, and Lake Hasuhai. Among the natural factors, evapotranspiration and runoff were secondary influences on these lake storage changes. This study provides a systematic analysis and attribution of water storage changes for major lakes in Inner Mongolia and provides scientific guidance for local water resource management and planning. Our method provides a useful example of using multi-mission satellite data for estimating water storage changes.