A comparative study of Meteosat, ECMWF, and radiosonde wind vectors at Istanbul

Wind vector evaluation through Meteosat is useful for a continental belt such as Turkey, where nationwide radiosonde and aircraft data are suboptimal, especially from the point of view of numerical weather prediction (NWP). Towards this goal, investigations have been carried out on the Meteosat cloud motion winds (CMW) using IR imagery with collocated radiosonde data in and around Istanbul with the eventual aim of extending this study to develop general circulation models in the Mediterranean region. The CMW analysis reveals correlation with the radiosonde data superior to that of the European Center for Medium range Weather Forecast (ECMWF) for the period of study. This study also confirms that Meteosat CMWs are subject to less severe speed biases, although there is a tendency to underestimate CMW speeds for low-wind-speed scenarios, as opposed to high wind speeds as suggested in the past studies. (C) Elsevier Science Inc., 2000.