Data Assimilation: the 1984/85 Revisions of the Ecmwf Mass and Wind Analysis

作者：D B Shaw, P. Lönnberg, Anthony Hollingsworth, Per Undén · 发表于：Quarterly Journal of the Royal Meteorological Society · 年份：1987 · DOI：10.1002/qj.49711347607 · 被引用次数：75 · 研究领域：Meteorological Phenomena and Simulations、Climate variability and models、Atmospheric Ozone and Climate

Abstract A comprehensive evaluation of the ECMWF operational data assimilation system has been made, based largely on statistics of its performance over a long period of time. the evaluation has identified many deficiencies, covering such aspects of the analysis as the optimum interpolation statistics, the data selection algorithms, and the quality control criteria applied within the analysis. The observation and forecast error variances were seriously in error in the stratosphere and in the tropics. A more faithful model of the forecast error spectrum is provided by the Bessel function expansion than by the Gaussian model. the vertical structure of the height error is assumed to be composed of two components: a ‘barotropic’ part related to a horizontally constant mode and a ‘baroclinic’ structure for the horizontally varying modes. the wind field errors also have a large‐scale component. the extratropical vertical correlation remained similar to the earlier correlations, but the tropical height and wind structures changed dramatically. Reasonable rejection limits were defined from the distributions of the observation departures from the first guess, as were observation errors for satellite and aircraft wind reports and Australian pseudo‐observations. A comprehensive and homogeneous data selection algorithm has been devised. However, it has been found necessary to exclude land surface wind reports from the analysis process as the wind departures from a first‐guess field commo...