Decline in Mediterranean rainfall caused by weakening of Mediterranean cyclones

Wet season (October-March) rainfall over the Northern Mediterranean has dec reased over the last four decades. The decline is being forced locally by a decrease in the intensity of cyclogenesis events in the region. The forcin g is subtle, since overall cyclone frequency exhibits no significant trend over time. The reduction in strength of the most intense cyclones is driven by recent trends observed in the coupled ocean-atmospheric circulation ove r the Northern Atlantic, in particular by the northwards migration of the m ain Atlantic storm-tracks.