Abstract
An observational network, dynamical models and data assimilation schemes are the three components of an ocean prediction system. Its configuration for a regional real-time forecasting system proceeds in three phases, based on previous knowledge and experience of the area. In the initial (exploratory) phase, identification of dominant scales (synoptic, mesoscale and submesoscale), processes and interactions is obtained. In the intermediate (dynamical) phase, a clear resolution of the important dynamics and events must be reflected in the nowcasts and forecasts. This is carried out via energy and vorticity analysis (EVA). The third phase is designed to validate the predictive capability of the forecasts. Both qualitative verification and quantitative skill are utilized. At each stage, high quality data sets are required. Observing System Simulation Experiments are essential to the development of the regional ocean prediction system. Initializations and updates are obtained by the fusion of multiple data streams, i.e., the melding of feature models, previous data driven simulations and observations. Nowcasts and forecasts are generated via sequential assimilation combining ship-acquired and sensed remote data. Nested models and nested observations are employed for adequate resolution. The approach is illustrated with recent real-time experiences at sea in the Iceland-Faeroe frontal region, the Straits of Sicily and the Eastern Mediterranean basin.