The Yunnan Guizhou Sichuan region has numerous rivers and is one of the regions with the richest water resources in China. Utilizing GRACE gravity satellite data and GLDAS hydrological model to invert groundwater reserves in the Yunguichuan region from 2003 to 2016, and verifying them with precipitation data. Using the empirical orthogonal function method to decompose the changes in water reserves in the region, analyze the factors affecting the interannual changes in groundwater reserves in the Yunguichuan region, and verify the correlation with TRMM precipitation data. The results indicate that GRACE and GLDAS can effectively invert groundwater reserves, with consistent trends and obvious seasonal variations; The variance contribution rate of the first two modes of significant annual cycle of water reserves change is 82.07%, of which the variance contribution rate of the first mode reaches 73.12%, and there is a relatively obvious annual cycle, which is highly consistent with the precipitation data in the same period. It can be concluded that precipitation plays a vital role in the change of groundwater reserves in Yunnan Guizhou Sichuan region
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