A COMPARISON OF SURFACE STRESS AND PRECIPITATION FIELDS IN SHORT-RANGE FORECASTS OVER THE ANTARCTIC REGION

A comparison is made of wind stresses derived from the European Centre for Medium-Range Weather Forecasts (ECMWF) and United Kingdom Meteorological Office (UKMO) operational numerical weather prediction models over the Antarctic region for the periods June 1 to July 27, 1988, and through July 1990. Comparison of model precipitation fields over the region is also made for the July 1990 period. Mean fields are found to be qualitatively similar over much of the Antarctic sea ice zone, with the largest discrepancy arising through the acceptance of an individual observation by one scheme in this data sparse region and rejection by the other. A particular feature of the comparisons is a large discrepancy in the values of the wind stress shown by the models around the Antarctic coastal zone. These are investigated in detail for the July 1990 period by reference to contemporaneous observations. Both precipitation and surface stress fields reveal a generally high similarity in their variability in space and time overall, illustrating the influence of the observational data on the model fields.