High-resolution Antarctic ice mass change jointly estimated by satellite gravimetry and altimetry

Abstract:

Accurate estimations of the ongoing Antarctic ice mass loss are critical to understand future ice mass loss and subsequent sea-level rise. Over the past two decades, changes in Antarctic ice mass have been accurately observed by GRACE gravity satellite, but its inherent low spatial resolution has led to limited examination in glacier-scale ice mass change. In this study, we improve the spatial resolution (~30km) of ice mass changes in Antarctica by combining observations from satellite gravimetry and altimetry. To this end, we revised both forward modeling and inversion of GRACE data by incorporating altimetry observation as a priori. The total mass changes in Antarctica estimated by the revised methods are consistent with the GRACE’s earlier observations, but their spatial patterns are analogous to the observations from satellite altimetry. Compared to the previous estimations by conventional GRACE data showing basin scales ice mass changes, our new results depict ice mass variations in the glacial scales. Such glacial scale ice mass change is validated by results from Input-Output method.