, 2010). Like other areas in a similar latitude, the Mediterranean region is a transitional zone with a large environmental meridional
gradient between humid mountains in the North and hot and arid regions in the South and is affected by both tropical and mid-latitude systems (Campins et al., 2011 and Lionello et al., 2006). However, the presence of a relatively large and deep mass of water makes the Mediterranean quite unique (Bolle, 2003), ranging its orography from depths to altitudes of the order of 5000 m and being communicated to the Atlantic through the Gibraltar strait. This water mass not only represents a heat reservoir and source of moisture for land areas but is also a source of energy that can be transformed into cyclone activity (Lionello et al., 2006). According to Nissen et al. (2010), 69%% of the wind storms are caused by cyclones (low pressure systems) NADPH-oxidase inhibitor located in the Mediterranean region while the remaining 31%% have their origin in the North Atlantic or Northern Europe. Although forced by planetary scale patterns, the complexity of the basin (e.g. sharp orography) produces many subregional and mesoscale features with a large spatial and seasonal variability (Campins et al., 2011). Winter Epigenetic activity and summer have contrasting patterns because
of the different cyclogenetic mechanisms taking place (Campins et al., 2011). Therefore, statistical analysis of climate data should be preferably performed for each season separately. During summer, cyclones/heat-lows are short-lived, weak and shallow, mainly caused by thermal contrasts and orographic effects (Campins et al., 2011). On the contrary, during winter, cyclones are well-developed depressions and tend to be deeper, longer-lived, more mobile and intense. Spring and autumn can be considered as transitional seasons between both extremes (Campins et al., 2011). Their different physical origins turn into different spatial distributions of low pressure system centres as well. Although the Gulf of Genoa area (located in the top-right corner of our study area,
see Fig. 2) exhibits a preferred area for cyclogenesis during the whole year, many summer low pressure systems develop over land (e.g. Sahara and Iberian Peninsula) indicating that thermal heating over land plays an important role in the genesis and maintenance new of such depressions. During winter, cyclones are located mainly over the sea with a clear maximum in the Genoa area (one of the areas with highest wind activity) and the Cyprus area (Eastern Mediterranean), the two locations of the maximum number of cyclone centres (Campins et al., 2011 and Nissen et al., 2010). These lower pressure areas located in the Gulf of Genoa produce a dominant NW wind field over the study area, causing the well-known regional Mistral (NW) wind, which is strengthened by the channelling effect of, for example, the Ebre valley (south of Catalan coast) and Rhone valley (in the Gulf of Lion).