Determination of Mass Changes in the Totten Glacier Basin, East Antarctica, Using an Improved Mascon Method With GRACE/GRACE‐FO Data

Abstract Global warming intensifies Antarctic ice sheet mass loss, significantly impacting sea level rise. The Totten Glacier Basin, a dynamic region in East Antarctica, critically influences global sea levels due to its substantial mass balance variability. Using Gravity Recovery and Climate Experiment (GRACE)/GRACE Follow‐On (GRACE‐FO) gravity data, we developed an enhanced mascon inversion method incorporating satellite altimetry data to analyze mass balance changes in the Totten Glacier Basin and its subbasins from 2002 to 2023. The basin exhibited a mass loss of −17.93 ± 0.43 Gt/yr, consistent with Center for Space Research (CSR), Jet Propulsion Laboratory (JPL), and German Research Centre for Geosciences (GFZ) mascon products (−18.19 ± 0.46 Gt/yr mean). The regional atmospheric climate model RACMO2.3p2 estimated higher losses (−25.00 ± 0.53 Gt/yr). Subbasin analysis revealed mass losses of −7.71 ± 0.15 Gt/yr (our estimate), showing consistent long‐term trends with CSR/JPL/GFZ means (−10.72 ± 0.12 Gt/yr) and RACMO2.3p2 (−11.88 ± 0.12 Gt/yr) despite spatial heterogeneity in magnitude. A generalized additive model (GAM) integrating climatic and environmental variables identified key drivers of mass balance changes: ice discharge, ocean temperature, surface pressure, evaporation, precipitation, Southern Hemisphere Annular Mode (SAM), and Southern Oscillation Index (SOI). Ice discharge and ocean temperature exerted dominant nonlinear impacts, while other factors exhibited spatiotemporal variability. These findings highlight the complex interplay of oceanic and atmospheric processes in Antarctic ice loss, emphasizing the need for multi‐scale observational and modeling approaches to refine sea level projections.