A catalogue and a classification of surface cyclones for the Western Mediterranean

Abstract

The Mediterranean Sea is a region that possesses a high frequency of cyclones. Many of them are lee depressions and so, mesoscale and weak, but others are strong and cover a wide area. In this study some characteristics of surface cyclones in the Western Mediterranean are presented. First a database was built from hand analyses of sea‐level pressure from 1992 to 1995. Next, a similar database was obtained from the LAM‐INM (Limited Area Model of the Instituto Nacional de Meteorología of Spain) objective analyses of the 1000 hPa geopotential field. Results show an important increase in the number of cyclones when a mesoscale analysis is carried out. Most of the Western Mediterranean cyclones are mesoscale and weak, and they are not uniformly distributed in space and in time. On the one hand, there are some areas with a high concentration of cyclones. The location of some of them, close to the main mountain ranges, suggests their possible orographic origin. On the other hand, in some areas the cyclones are present during the whole year, but in other areas are seasonally distributed. Finally, a study of typologies of the cyclones was conducted by using the cluster analysis technique. The classification was performed from the intensity of the cyclones and the shape of the sea‐level pressure around the centre. Results are similar from both databases and so the existence of seven typologies have been identified. Copyright © 2000 Royal Meteorological Society

Three millennia of heavy rainfalls in Western Mediterranean: frequency, seasonality and atmospheric drivers

“…S2). The scarce summer HR events are caused by convective storms, a consequence of thermal related low pressure over the Iberian Peninsula12.…”

Lagrangian dynamics of the mistral during the HyMeX SOP2

“…In summer it is generally weaker than in fall and winter and can sometimes combine with sea breeze [ Bastin et al , , ; Drobinski et al , ]. The mistral is frequently observed to extend as far as a few hundred kilometers from the coast [ Jansá , ; Salameh et al , ] and is one of the primary causes of storms over the Mediterranean [ Trigo et al , ; Campins et al , ]. The mistral is often associated with the tramontane, a companion wind which blows from the northwest along the Aude valley between the Pyrénées and the Massif Central [ Georgelin and Richard , ; Drobinski et al , ].…”

Coupled atmosphere‐ocean‐wave simulations of a storm event over the Gulf of Lion and Balearic Sea

“…The high frequency and intensity of these winds is a direct consequence of the frequency and intensity of these Mediterranean cyclones [ Lionello et al , 2002]. Cyclogenesis is dependent on the season [ Trigo et al , 1999; Campins et al , 2000; Buzzi and Speranza , 1986; Lionello et al , 2006] and, as suggested by Jansá et al [1994] and Alpert and Ziv [1989], is sustained and intensified by latent heat flux and air‐sea temperature contrast. Low pressure systems can then travel from the Iberian Catalan coast to the Balearic Islands and turn on the GoL where they generate or induce intense local acceleration [ Campins et al , 1995] of the Mistral and Tramontane winds and enhance the air‐sea interactions.…”