Redefinition of the Amery Ice Shelf, East Antarctica, grounding zone

• Published in: Journal of Geophysical Research
• Main Authors: Fricker, HA, Allison, I, Craven, M, Hyland, G, Ruddell, A, Young, NW, Coleman, R, King, MA, Krebs, K, Popov, S
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2002
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Glaciology; Amery; Amery Ice Shelf; East Antarctica; Antarc*; Antarctica; Ice Shelf
• Online Access: https://doi.org/10.1029/2001JB000383; http://ecite.utas.edu.au/25661

New 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 73.2S. 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 72.98S. 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.