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Abstract

The mass loss in the Greenland Ice Sheet (GrIS) has significant impacts on sea level rise, water cycle balance, and even global climate stability. The Gravity Recovery and Climate Experiment (GRACE) satellites are widely utilized to investigate the GrIS mass changes, but its spatial resolution is limited, resulting in large signal leakage into the ocean and the interior of GrIS. Therefore, we proposed a novel weighted forward modeling (WFM) method, which treat the high spatial resolution surface elevation change data driven by the satellite altimetry as spatial weighting factors to pinpoint total mass change form satellite gravimetry. To understand the performance of the novel WFM method, we design close-loop numerical study, which shows that WFM method has better spatial distribution accuracy, correlation and root mean square error (RMSE) than the ordinary forward modeling (FM) method. In the real data analysis, the WFM method was used to estimate the high-resolution mass changes of GrIS and its 19 sectors from 2003 to 2017. The independent mass balance data based on the Input-output method is utilized for verification, and compared with the FM method. The results showed that the average trend bias of the WFM method was 5.8 Gt/yr and the average RMSE was 25.4 Gt, which improved by 27.8% and 26.8% relative to the FM solution. And the WFW based on solutions are in good agreement with the mascon products released by CSR, JPL and GSFC. The WFM solution can improve our understanding of the small-scale GrIS mass variation characteristics.