21st Projections of precipitation extremes in the Mediterranean from a medium resolution GCM

Precipitation extremes simulated by a medium resolution GCM ( INMCM3.0) are analyzed for the Mediterranean region. A structured analysis of low frequency variability in the control and forced ( corresponding to the IPCC scenarios) model runs is performed. The preliminary results of the analysis of rainfall patterns under global warming conditions, during the extended winter ONDJFM season, show an increase of rainfall extremes in both frequency and intensity in northern Europe and a decrease in the most part of Mediterranean. In the latter region an increase of dry conditions is also observed. The change in the rainfall patterns can be explained by a northward shift of the North Atlantic winter storm track. This shift is related changes in meridional and zonal surface temperature gradients ( Equator- Pole and Ocean-Land contrast, respectively) due to anthropogenic forcing. Changes in the inter-annual and multi-decadal natural variability are also noted.