Systematic errors of the ECMWF operational forecasting model in mid‐latitudes

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Arpe, K., Klinker, E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1986
• Subjects: Bering Strait; Canada; Siberia
• Online Access: http://dx.doi.org/10.1002/qj.49711247111; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.49711247111; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.49711247111

Abstract The systematic errors of the ECMWF spectral operational model (April 1983 to April 1985) in midlatitudes are described. The main errors are: * a zonalization of the time‐mean flow with considerably reduced diffluent flow at the jet exits; * a wavenumber‐2 pattern in the mean height error field with forecast heights too low over Europe and the Bering Strait, and too high over Canada and Siberia; * an upward shift of the subtropical jet and the tropopause; * a cooling of the stratosphere; * a cooling of the middle troposphere which decreases the static stability in the lower troposphere; * an increase of the horizontal and vertical tilts of baroclinic waves; * changes in the geographical distributions of baroclinic waves and cyclones, with enhanced activity near jet exits and reduced activity near areas of cyclogenesis; * a drop of eddy kinetic energy during the 10‐day forecasts, first in the baroclinic waves and later in the long waves. The errors in both hemispheres have similar characteristics. The relations between the different errors and possible causes are discussed and comparisons with the errors of the former ECMWF operational grid point model are made. The introduction of the spectral model has led to significant improvements in the speed of baroclinic waves, which are now predicted more accurately up to day 3.