Pressure field over Europe and North Atlantic favourable for the occurrence of clear and cloudy days in Poland

In this paper, results of research concerning circulation conditions favouring the occurrence of elear and cloudy days in Poland are presented. An analysis of the mean pressure field over North Atlantic and Europe on such days was performed, differences between the mean pressure on such days and the mean pressure from all the days of the period 1966-2000 were determined. The pressure field was characterised by mean daily values taken from grid nodes from the area with (p 30°-70°N and X 40°W-60°E (NCEP/NCAR database). The relation between the am ount of cloudiness over Poland and pressure was estim ated by means of linear correlation coefficient.