Considerations on the dynamics of a cold spell over Greece

Abstract

A cold spell was observed in March 1987 over Greece, which was characterised by extremely low temperatures and heavy snowfall. The dynamic and thermodynamic characteristics of this rather unusual event are investigated using ECMWF analyses. First, the time evolution of the spell at upper and lower levels is briefly described. Since the persistence of the cold spell is significant, its mean behaviour and vertical structure are then examined. Therefore, the dynamic parameters under consideration have been averaged over the time period of 4 to 11 March 1987. It is found that the cold spell is characterised by a tropopause lowering, associated with a maximum of relative vorticity and very cold air over the Balkan Peninsula. Intense cold air is observed throughout the troposphere over the area, with ascending motion at the eastern boundary of it. In addition, a baroclinic zone of the potential and equivalent potential temperature is pronounced at the low levels.

Keywords

• snowfall
• tropopause
• vorticity
• balkan peninsula
• troposphere
• griechenland
• kaltlufttropfen