Modeling the basal melting and marine ice accretion of the Amery Ice Shelf

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Galton-Fenzi, BK, Hunter, JR, Coleman, R, Marsland, SJ, Warner, RC
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2012
• Subjects: Earth Sciences; Oceanography; Physical Oceanography; Amery; Amery Ice Shelf; Antarc*; Ice Shelf; Sea ice
• Online Access: https://doi.org/10.1029/2012JC008214; http://ecite.utas.edu.au/79215

The basal mass balance of the Amery Ice Shelf (AIS) in East Antarcticais investigated using a numerical ocean model. The main improvements ofthis model over previous studies are the inclusion of frazil formation and dynamics, tides and the use of the latest estimate of the sub-ice-shelf cavitygeometry. The model produces a net basal melt rate of 45.6 Gt year −1 (0.74 m ice year −1 ) which is in good agreement with reviewed observations. The melting at the base of the ice shelf is primarily due to interaction with High Salinity Shelf Water created from the surface sea-ice formation in winter. The temperature difference between the coldest waters created in the open ocean and the in situ freezing point of ocean water in contact with the deepest part of the AIS drives a melt rate that can exceed 30 m of ice year −1 . The inclusion of frazil dynamics is shown to be important for both melting and marine ice accretion (refreezing). Frazil initially forms in the supercooled water layer adjacent to the base of the ice shelf. The net accretion of marine ice is 5.3 Gt year −1 , comprised of 3.7 Gt year −1 of frazil accretion and 1.6 Gt year −1 of direct basal refreezing.