The effects of ocean warming on melting and ocean circulation under the Amery Ice Shelf, East Antarctica

Abstract

Using a three-dimensional ocean model specially adapted to the ocean cavity under the Amery Ice Shelf, we investigated the present ocean circulation and pattern of ice-shelf basal melting and freezing, the differences which would result from temperature changes in the seas adjacent to the Amery Ice Shelf, and the ramifications of these changes for the mass balance of the ice shelf. Under present conditions we estimate the net loss from the Amery Ice Shelf from excess basal melting over freezing at approximately 7.8 Gt a-1. This comprises a gross loss of 11.4 Gt a-1 at a mean rate of 0.42m a-1, which is partially offset by freezing-on of 3.6 Gt a-1, at a mean rate of 0.19m a-1. When the adjacent seas were assumed to warm by 1°C, we found the net melt increased to 31.6 Gt a-1, comprising 34.6 Gt a-1 of gross melt and 3.0 Gt a-1 of freezing.