Antarctic moisture flux and net accumulation from global atmospheric analyses

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Abstract
Previous attempts to derive the Antarctic surface net accumulation distribution from atmospheric-moisture fluxes, in reasonable agreement with the observed distribution, have encountered many difficulties. The present analysis uses the Australian Bureau of Meteorology Global Atmospheric Assimilation and Prediction Scheme (GASP), which has been operational since 1989, to derive the net air-mass and moisture fluxes over the Antarctic. It is shown that the annual mean net surface accumulation closely resembles the glaciologically observed distribution and provides a physical basis for the observed pattern, through the moisture transports. The variations with latitude and elevation and through the annual cycle are also well reproduced. Although some mass-closure errors still exist, they are expected to become insignificant with the new generation of improved analysis schemes. Consequently the atmospheric analyses can provide a sound basis for both assessing the performance of global climate models in simulating Antarctic accumulation rates and monitoring long-term changes which may occur with global warming.