MyWave-D1.4 - Report on Wave Coupling

This deliverable concerns the coupling between two, meteorological and wave, models. One way (meteo to waves) coupling has been for a long while the norm, but Janssen (1989, 1991) showed that a two-way coupling, where the wave effect is transmitted back to the atmosphere, represents the correct physics, in so doing improving the results in also the meteorological model. It has also been suggested that a two-way coupling would be more and more effective with increasing resolution. While the European Centre for Medium-Range Weather Forecasts (Reading, U.K.) has implemented the full coupling on a global scale since 1991, the matter has not received much attention at higher resolution, i.e. the local scale. In the MyWave project one of the targets was the implementation of a fully coupled system in the Mediterranean. Two actions have been taken in this respect, by the Italian Meteorological Service (henceforth CNMCA) together with the Institute of Marine Sciences (ISMAR), and by the Greek Hellenic Centre for Marine Research (HCMR). In the following pages the two systems, that use different meteorological models, are described. Given that the basic theory is the same, the two implementations are described in parallel, describing first the two backgrounds and the respective meteorological models. The wave model, WAM, is the same for both the systems. Then he respective test periods are described, each together with the related results. In the conclusion we summarize the overall results, also in the perspective of further developments.