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Abstract

The basal mass balance of the Amery Ice Shelf (AIS) in East Antarctica is investigated
using a numerical ocean model. The main improvements of this 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 cavity geometry. 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.

Item Type:	Article
Authors/Creators:	Galton-Fenzi, BK and Hunter, JR and Coleman, R and Marsland, SJ and Warner, RC
Journal or Publication Title:	Journal of Geophysical Research
ISSN:	0148-0227
DOI / ID Number:	10.1029/2012JC008214
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