Study of Cold Anticyclones Generating in the Mediterranean

Abstract

A comprehensive climatology of anticyclones affecting the Mediterranean has been assembled employing the objective finding and tracking scheme of the University of Melbourne (MS). The identified anticyclones have been characterized as cold or warm on the basis of their thermal structure at the lower isobaric levels with the aid of an extension module of MS that enables the examination of the vertical thermal extent of synoptic systems. The aim of the present study is to get a perspective of the processes involved in the formation of surface anticyclones. The mean and anomaly fields and the system-centered composites of several atmospheric variables are studied throughout the troposphere, taking under consideration the position of the systems and the season of the year at the time of formation. The present analysis is confined to cold-core systems and focuses on the areas of anticyclogenetic maxima in order to ensure the statistical robustness. The synergy of the low-level cooling and the upper-level dynamics is confirmed for the northern examined areas for both seasons, while anticyclogenesis over central and eastern African areas seems to be mainly governed by thermal processes.