SYSTEMATIC FORECAST ERROR IN U.S.NMC OPERATIONAL SPECTRAL MODEL

The distribution of monthly mean error of NMC model forecasts and its seasonal variation are investigated.The ratio of monthly mean error to standard deviation is used here to find out that the region where a correction of systematic error is needed and appropriate is mainly in low latitudes.The improvement,after the model's vertical resolution and some physical parameters were changed from April 1985,is investigated,and the NMC operational model forecasts have also compared with those of ECMWF.