Mass changes of the Antarctic Peninsula ice sheet and peripheral glaciers, 2007–202

Abstract

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea-level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is too coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 × 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost 28 ± 6 Gt a−1 while its peripheral glaciers lost 14 ± 3 Gt a−1. For the AP Ice Sheet, our new estimate is 4 to 5 times more negative than the one obtained in IMBIE using altimetry data (-5.2 ± 1.8 Gt a−1 from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.