Sensitivity of the Amery Ice Shelf, Antarctica, to Changes in the Climate of the Southern Ocean

Abstract

Coupled ocean?atmospheric general circulation models indicate that warming of up to 3°C may occur over the next century in waters immediately to the north of the Amery Ice Shelf. The impact of this warming on the ocean cavity under the Amery Ice Shelf and the mass exchange at the interface between the ocean cavity and the ice shelf is investigated using a three-dimensional ocean model. Warming of between 0.25° and 3.0°C is applied along the ice front in a series of model runs, rather than in a single transient run. Changes in salinity are also considered for larger amounts of warming. The model results show that the circulation in the ocean cavity changes as warming increases, particularly in the gyres that dominate the horizontal circulation. The changes in the heat flux from the warming increase the melt rates from the base of the Amery Ice Shelf, from the present-day mean melt rate and net mass loss estimates of 0.28 m yr?1 and 14.2 Gt yr?1, respectively, by approximately 0.55 m yr?1°C?1 and 28.4 Gt yr?1°C?1. The maximum melt rates increase much more strongly, by around 10 m yr?1°C?1. These increased rates of melting suggest substantial modification of the ice shelf would occur in a warmer climate, particularly near the grounding line, and thus indicate that warming of the oceans around Antarctica has the potential for significant impact on the Antarctic ice sheet.