A Novel Approach Combining GRACE(‐FO) and Altimetry Reveals a Recent East‐to‐West Shift in the Slowdown of Glacier‐Scale Mass Loss in the Greenland Ice Sheet

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Abstract The mass loss of the Greenland Ice Sheet (GrIS) has profound impacts on sea levels, the water cycle, and global climate variability. The Gravity Recovery and Climate Experiment (GRACE) and its follow‐on mission (GRACE‐FO) provide accurate but limited spatial resolution observations of GrIS mass changes. Therefore, we developed a novel multi‐time scale weighted forward modeling (WFM) approach that combines GRACE(‐FO) observations with satellite altimetry data to improve mass change estimations in the GrIS at high‐resolution (25 km × 25 km). The WFM solution effectively represents the glacier‐scale interannual mass variations, with an average correlation of 0.71 with the Input‐Output method, higher than Mascon products. The WFM solution reveals a spatial pattern of glacier mass change from 2020 to 2023, indicating that the slowdown in the GrIS glacier mass loss has shifted from the east to the west compared to 2013–2018; the mass loss rate decreased by 44.9 ± 1.04 Gt/yr in the western GrIS and increased by 42.3 ± 0.98 Gt/yr in the eastern GrIS. The most pronounced mass loss slowdown occurred at Jakobshavn Glacier (7.3 ± 0.07 Gt/yr). In this pattern, the trough of low‐pressure west of the GrIS moved westward, and a high‐pressure anomaly over the North Atlantic south of the GrIS intensified southwesterly winds over the GrIS. These winds transported warmer, moister air from the Atlantic toward the western GrIS, leading to increased snowfall and rainfall, thereby promoting glacier mass accumulation. If this pattern continues, it could benefit the preservation of the ice in the western GrIS.

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