A Comparison of Five Numerical Weather Prediction Analysis Climatologies in Southern High Latitudes

Abstract

In this paper, numerical weather prediction analyses from four major centers are compared?the Australian Bureau of Meteorology (ABM), the European Centre for Medium-Range Weather Forecasts (ECMWF), the U.S. National Centers for Environmental Prediction?National Center for Atmospheric Research (NCEP?NCAR), and The Met. Office (UKMO). Two of the series?ECMWF reanalysis (ERA) and NCEP?NCAR reanalysis (NNR)?are ?reanalyses?; that is, the data have recently been processed through a consistent, modern analysis system. The other three?ABM, ECMWF operational (EOP), and UKMO?are archived from operational analyses. The primary focus in this paper is on the period of 1979?93, the period used for the reanalyses, and on climatology. However, ABM and NNR are also compared for the period before 1979, for which the evidence tends to favor NNR. The authors are concerned with basic variables?mean sea level pressure, height of the 500-hPa surface, and near-surface temperature?that are available from the basic analysis step, rather than more derived quantities (such as precipitation), which are available only from the forecast step. Direct comparisons against station observations, intercomparisons of the spatial pattern of the analyses, and intercomparisons of the temporal variation indicate that ERA, EOP, and UKMO are best for sea level pressure;that UKMO and EOP are best for 500-hPa height; and that none of the analyses perform well for near-surface temperature.