Coupled atmosphere ocean climate model simulations in the Mediterranean region: Effect of a high-resolution marine model on cyclones and precipitation

Abstract

In this study we investigate the importance of an eddy-permitting Mediterranean Sea circulation model on the simulation of atmospheric cyclones and precipitation in a climate model. This is done by analyzing results of two fully coupled GCM (general circulation models) simulations, differing only for the presence/absence of an interactive marine module, at very high-resolution (∼ 1/16◦), for the simulation of the 3-D circulation of the Mediterranean Sea. Cyclones are tracked by applying an objective Lagrangian algorithm to the MSLP (mean sea level pressure) field. On annual basis, we find a statistically significant difference in vast cyclogenesis regions (northern Adriatic, Sirte Gulf, Aegean Sea and southern Turkey) and in lifetime, giving evidence of the effect of both land-sea contrast and surface heat flux intensity and spatial distribution on cyclone characteristics. Moreover, annual mean convective precipitation changes significantly in the two model climatologies as a consequence of differences in both air-sea interaction strength and frequency of cyclogenesis in the two analyzed simulations.