Climate Modeling Over the Mediterranean Region: An Overview

Saharan dust generation, transport and deposition over the Mediterranean depends on the prevailing atmospheric circulations and climatic conditions over the region. Different sets of models can be used to simulate these circulations and their possible response to changes in climatic forcings (e.g. greenhouse gas concentration): General Circulation Models (GCMs) and Regional Climate Models (RegCMs). GCMs provide numerical representations of the global atmosphere and are the primary tools today available for climate simulation. However, for an area such as the Mediterranean Basin, characterized by complex topographical and coastline features, their resolution (typically a few hundred km) is too coarse to capture the details of regional circulations. A finer model resolution (a few tens of km) can be obtained using RegCMs driven by initial and lateral boundary conditions either from analyses of observations or from GCM output. Alternatively, climate simulation on finer scales can be achieved through the use of variable resolution global models. This paper presents a brief review of the performance of GCMs over the Mediterranean Basin and of the application of RegCMs and variable resolution models to study climatic conditions over the region. The implications concerning the use of GCMs and RegCMs to study the effects of African dust across the Mediterranean are discussed.