Frontal depressions over the Mediterranean sea and central southern Europe. Les perturbations frontales au-dessus de la mer Méditerranée et de l'Europe centrale méridionale

Abstract

An analysis of the frequency of occurrence of frontal depressions over central-southern Europe and the Mediterranean Sea was carried out based on daily synoptic charts for a nine year period from 1971 to 1979. The frontal depressions are classified into five types (A, B, C, D, E) based on the regions in which they originally formed. Tables and charts are presented showing the annual and seasonal frontal depression frequencies over the area. Also, the variation of average frequency of frontal depressions with latitude and longitude is demonstrated. The distribution of the frequency of frontal depressions fits in with generally accepted models of hemispheric circulation. The mean tracks of the frontal depression centres were determined. The ten individual tracks are shown together in a map and they emphasize the way in which so many frontal depression centres migrate towards Corsica and nothern Italy from various points in the west of the study area.