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Redefinition of the Amery Ice Shelf, East Antarctica, grounding zone
journal contribution
posted on 2023-05-16, 13:56 authored by Fricker, HA, Ian AllisonIan Allison, Craven, M, Glenn HylandGlenn Hyland, Ruddell, A, Neal YoungNeal Young, Richard ColemanRichard Coleman, Matt KingMatt King, Krebs, K, Popov, SNew evidence is presented which shows that the Amery Ice Shelf, East Antarctica, extends ∼240 km upstream of the previously reported position. We combine a digital elevation model of the Amery Ice Shelf created from ERS-1 satellite radar altimetry with measured ice thicknesses and a simple density model in a hydrostatic (buoyancy) calculation to map the extent of the floating ice. This reveals that the ice is floating as far south as 73.2°S. The result is confirmed by static GPS measurements collected during three consecutive field campaigns on the Amery Ice Shelf where the vertical component of the GPS shows a clear tidal signal at 72.98°S. Other evidence for the grounding zone position comes from an analysis of satellite imagery, mass flux calculations, and ice radar data. The southward extension of the grounding line substantially alters the shape and dimensions of the ocean cavity beneath the ice shelf, which has implications for modeling studies of sub-ice shelf processes, such as basal melting and freezing, ocean circulation, and tides. The new grounding line position will also improve geophysical studies, where the computation of ocean tidal loading corrections is important for postglacial rebound estimates and correction of satellite altimetry measurements within the region.
History
Publication title
Journal of Geophysical ResearchVolume
107Issue
B5Pagination
2092ISSN
0148-0227Department/School
Institute for Marine and Antarctic StudiesPublisher
American Geophysical UnionPlace of publication
Washington, DCRepository Status
- Restricted