A MESOSCALE MODELING STUDY OF THE ATMOSPHERIC CIRCULATION OF HIGH SOUTHERN LATITUDES

The meteorology of high southern latitudes during winter is simulated using a cloud-free version of The Pennsylvania State University-Nation al Center for Atmospheric Research Mesoscale Model version 4 (MM4) wit h a 100-km horizontal resolution. Comparisons between idealized simula tions of Antarctica with MM4 and with the mesoscale model of Parish an d Waight reveal that both models produce similarly realistic velocity fields in the boundary layer. The latter model tends to produce slight ly faster drainage winds over East Antarctica. The intensity of the ka tabatic winds produced by MM4 is sensitive to parameterizations of bou ndary layer fluxes. Two simulations are performed with MM4 using analy ses from the European Centre for Medium-Range Weather Forecasts for Ju ne 1988 as initial and boundary conditions. A simulation of the period from 0000 UTC 2 June to 0000 UTC 8 June produces realistic synoptic p henomena including ridge development over East Antarctica, frontogenes is over the Amundsen Sea, and a katabatic surge over the Ross Ice Shel f. The simulated time-averaged fields for June 1988, particularly that of a 500-hPa height, are in good agreement with time-averaged fields analyzed by the European Centre for Medium-Range Weather Forecasts. Th e results of the simulations provide detailed features of the Antarcti c winter boundary layer along the steeply sloping terrain. Highest bou ndary layer wind speeds averaged over the month-long simulation are ap proximately 20 m s(-1). The lack of latent heating in the simulations apparently results in some bias in the results. In particular, the clo ud-free version of MM4 underpredicts the intensity of lows in the sea level pressure field.