Simulations of Antarctic climate using a limited area model

A Limited area model is nested within the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses and climate simulations are performed for July at a resolution of 125 km for a domain located over the continent of Antarctica. The model displays negative biases of mean sea level pressure off the coast of East Antarctica, and positive biases in other oceanic regions close to the coast of the continent. Biases of surface air temperature are generally modest over the continent; the quality of the temperature simulation is more difficult to assess over the areas of sea ice close to the coast, as the ECMWF analyses do not include an open water fraction. The model simulation of snow accumulation is good; the observed positive gradient of accumulation between the center of Antarctica and the coast is reproduced well, although precipitation is generally too high over regions of significant orography. Comparison between simulations performed with and without oceanic leads shows that leads increase sensible and latent heat fluxes over regions of sea ice, and increase accumulation over the continent of Antarctica. The effects of the introduction of leads into the limited area model are consistent with the results of similar general circulation model (GCM) sensitivity tests previously performed.