A STUDY OF FROST EVENTS IN AREAS CHARACTERIZED BY THE ABSENCE OF OBSERVATIONS

Serious events of radiative frost were reported in an important agricu ltural area of central Macedonia, the valley of Lagadas, at the end of March 1994. Since the phenomenon has a strong local character and no surface observations are available, a simulation is performed using a three dimensional numerical model in order to investigate the horizont al and vertical thermal structure of the lower troposphere during the frost event. The synoptic analysis reveals that the background flaw wa s weak, associated with anticyclonic circulation and insignificant pre ssure gradient in the lower troposphere. Under these synoptic conditio ns, it was demonstrated that the meteorological model represents succe ssfully the temperature and wind fields over the valley of Lagadas dur ing the frost event. It appears that the model can serve as an alterna tive method to analyse the characteristics of the radiative frost that occurs very frequently over the examined area associated with substan tial economic repercussion.