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

Wind vector evaluation through Meteosat is useful for a continental belt su ch as Turkey, where nationwide radiosonde and aircraft data are suboptimal, especially from the point of view of numerical weather prediction (NWP). T owards this goal, investigations have been carried out on the Meteosat clou d motion winds (CMW) using IR imagery with collocated radiosonde data in an d around Istanbul with the eventual aim of extending this study to develop general circulation models in the Mediterranean region. The CMW analysis re veals 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 spee d 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 pa st studies. (C) Elsevier Science Inc., 2000.