An assessment of operational Antarctic analyses based on data from the FROST Project

Volume 14, Issue 6 (December 1999) Add to Favorites Email Download to Citation Manager Track Citations Glossary Permissions -------------------------------------------------------------------------------- Full-text PDF Turner, John, Steven Leonard, Gareth J. Marshall, Michael Pook, Lance Cowled, Richard Jardine, Stephen Pendlebury, Neil Adams, 1999: An Assessment of Operational Antarctic Analyses Based on Data from the FROST Project. Wea. Forecasting, 14, 817–834. doi: http://dx.doi.org/10.1175/1520-0434(1999)0142.0.CO;2 An Assessment of Operational Antarctic Analyses Based on Data from the FROST Project John Turner, Steven Leonard, and Gareth J. Marshall British Antarctic Survey, Cambridge, United Kingdom Michael Pook Institute of Antarctic and Southern Ocean Studies, University of Tasmania, Hobart, Australia Lance Cowled, Richard Jardine, and Stephen Pendlebury Bureau of Meteorology, Hobart, Australia Neil Adams Antarctic Cooperative Research Centre and Bureau of Meteorology, Hobart, Australia Abstract The quality of the Antarctic operational analyses that were distributed over the Global Telecommunications System during the First Regional Observing Study of the Troposphere project special observing period of July 1994 is considered. Numerical analyses from the U.K. Meteorological Office, the European Centre for Medium-Range Weather Forecasts, the Australian Bureau of Meteorology, and the U.S. National Centers for Environmental Prediction are compared with high quality analyses prepared using all available late data and high-resolution satellite imagery. The subjective assessment of the analyses indicated that no large, synoptic-scale systems were missing, but major discrepancies were found in terms of the depth of the lows, location errors, and failures to resolve the complexities of systems. Generally, the central pressures of the lows were handled better than the locations of the centers. Only 4 lows out of a total of 161 in the Eastern Hemisphere during the period 22–28 July had to be relocated more than 500 km. High-quality satellite imagery was very important in correcting the locations of the lows and in resolving the structure of multicentered systems, which were often found to be much more complex than analyzed on the operational charts. The satellite imagery was of less value over the continent since some of the lows here, which were analyzed using automatic weather station data, had no cloud associated with them as a result of the atmosphere being very dry. Few changes were made to the positions of anticyclones and only minor modifications to ridges were required. The mean pressure at mean sea level fields for July 1994 as produced by the four models were all very similar, but the Australian model stood out as slightly different over the Amundsen Sea because of large differences in the handling on one large low during the early part of the month. The Phillpot technique for the analysis of the 500-hPa surface over the interior of the continent was of particular value in resolving structure in the circulation.

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