Impact of ocean–atmosphere coupling on future projectionof Medicanes in the Mediterranean sea

The Mediterranean basin is one of the main cyclogenetic regions in the world. This is likely due to the orographic conditions, as well as the thermodynamic
characteristics found over the Mediterranean. Among the large amount of cyclones that develop in this area, cyclones with tropical characteristics called medicanes (“Mediterranean Hurricanes”) eventually develop in the Mediterranean Sea. They have large harmful potential and a correct simulation of their evolution in climate projections is important for an adequate adaptation to climate change. Different studies suggest that ocean–atmosphere coupled models provide a better representation of medicanes, especially in terms of intensity and frequency. In this work, we use the regionally coupled model ROM and its stand-alone atmospheric component (REMO) that in this work is used as uncoupled model to study how air-sea interactions affect the evolution of medicanes in future climate projections. We find that under the RCP8.5 scenario our climate simulations show an overall frequency decrease which is more pronounced in the coupled than in the uncoupled configuration, whereas the intensity displays a different behaviour depending on the coupling. These changes could be explained due to the decrease in the number of extratropical cyclones and the increase of atmospheric stability conditions. In the coupled run, the relative frequency of higher-intensity medicanes increases, but this is not found in the uncoupled simulation. Also, this study indicates that the coupled model simulates better the summer minimum in the occurrence of medicanes, avoiding the reproduction of unrealistically intense events that can be found in summer in the uncoupled model.