Influences of orography on the Adriatic sirocco wind

Operational oceanography of the Mediterranean Sea has received significant attention in recent years. The Adriatic Sea in particular is covered by a regional hydrodinamical model and several shelf models, where the necessary boundary conditions are prescribed by simple one-way nesting between respective models. The atmospheric forcing has been taken from the global ECMWF model having 0.5 degrees longitude and latitude resolution.

Differences between meteorological fields over the Adriatic Sea as predicted by the regional meteorological model ALADIN and the global ECMWF model are analyzed. The focus is on the sirocco episodes between November 2002 and September 2003. Results indicate that the orography, namely Gargano Mountains and Apennines, has a significant effect on the sirocco airflow. It is shown that the Gargano Mountains induce the typical structure of the flow past the 3D obstacle in the lee that influences the wind-curl field. While the ALADIN model resolves the structure, the coarser ECMWF model is unable to do so. Consequently, different atmospheric forcing may result in different impact of the sirocco wind on the Western Adriatic Current.