SYSTEMATIC ERRORS IN U. S. A. OPERATIONAL SPECTRAL MODEL FORECASTS

The distribution of monthly mean errors and its seasonal variations are investigated.The ratio of monthly mean error to standard deviation is used to find out where the systematic errors should be applied. These areas are mainly in low-latitude.The improvements made after the vertical resolution and some physical parameters had been changed for April 1985 were investigated. The quality of U.S.A. operational model forecasts have also compared with ECMWF.