Grounding Zone of Amery Ice Shelf, Antarctica, From Differential Synthetic‐Aperture Radar Interferometry

• Published in: Geophysical Research Letters
• Main Authors: Hanning Chen, Eric Rignot, Bernd Scheuchl, Shivani Ehrenfeucht
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: Geophysics. Cosmic physics; QC801-809; Amery Ice Shelf; Antarc*; Antarctica; East Antarctica; Ice Shelf
• Online Access: https://doi.org/10.1029/2022GL102430; https://doaj.org/article/a3e4113c04ff4ddea565b9547749efbf

Abstract We employ a time series of Sentinel‐1 differential radar interferometry data from 2018 to detect the variability in grounding line position of the Fisher, Mellor, and Lambert glaciers, which drain about 47 billion tons of ice per year from East Antarctica. We observe kilometer‐scale tidal migration, two orders of magnitude larger than expected for ice flowing over a hard bed. The migration is not in phase with changes in oceanic tide. In two estuaries underlaid by subglacial channels, we observe two states of migration that switch on and off over time scales of several weeks. The range of vertical motion reveals a water column thickness of 2–20 cm. Such intrusions of seawater over wide grounding zones are not accounted for in physical models. Including them will add vigorous melting of grounded ice that will enhance the sensitivity of glaciers to ocean warming and increase projections of mass loss.