We examine the circulation of the Adriatic Sea during fall 1999 using the Navy Coastal Ocean Model (NCOM), with surface forcing provided by the atmospheric component of the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS). Separate three-dimensional multivariate optimum interpolation (MVOI) analysis techniques are used to generate the initial conditions for both COAMPS and NCOM. First, we used a 6-km NCOM grid over the entire Mediterranean Sea, with forcing supplied by surface stresses from a 27-km COAMPS grid, also covering the entire Mediterranean Sea area. Both the atmospheric and ocean fields produced were part of independent 12-hour incremental data assimilation cycles over the time period of interest. The resulting NCOM forecasts were then used as lateral boundary conditions for a series of higher resolution (2 km) NCOM forecasts of the Adriatic Sea. In these forecasts, a set of surface stress fields from COAMPS, using a nested 4 km grid centered over the Adriatic Sea, were used to force the NCOM high-resolution ocean nest.

These ocean modeling studies are particularly timely as there are several observational studies planned for the Adriatic Sea in the next two years. These programs, the Adriatic Current Experiment and Euro-STRATAFORM, will generate much data about the circulation of this shallow sea subjected to floods from local rivers and strong bora wind events. A goal of our modeling work is to understand the response pattern of the Adriatic to the complex combined forcing of the bora winds and strong river run-off.