EVALUATION OF THE ALADIN/LACE MESOSCALE MODEL DURING THE MAP SOP EXPERIMENT

The time series of temperature, wind speed and wind direction of the ALADIN/LACE (Limited Area Modelling for Central Europe) mesoscale model were compared with the radio-sounding data obtained above Zagreb during the Mesoscale Alpine Programme Special Observing Period (MAP SOP, Sept-Nov 1999). The evaluation was done at the 850 hPa level and at 988 m above mean sea level. The latter was chosen to test the usability of the Puntijarka station data as a substitute at 988 m during periods when radio-sounding observations are not available. The forecast values of temperature and, to some extent, wind direction agree better with the observed data than the forecast values of wind speed. The forecast skill decreases with the forecast range. The modelled temperature is slightly overestimated; in contrast, wind speed is slightly underestimated. The accuracy of the prognostic temps (pseudoTEMP) of the direct ALADIN/LACE mesoscale model output is somewhat smaller at 988 m, very likely due to the influence of surface forcing. The temperature measured at the Puntijarka station agrees better with radio-sounding data than wind speed and wind direction. The time series of temperature are subjected to a seasonal tendency variation, that makes these data usable only in periods when there is no tendency. In contrast, because of the existence of huge tendencies, raw wind speed and wind direction data are, in general, not suitable for the purpose of the model verification or initialisation