At IPMA the sea state forecasts are based on three numerical models. Two such models are developed in the ECMWF (www.ecmwf.int), namely the WAve Model (WAM), global model with a spatial resolution of 0.25º, and the limited area model European Shelf Model (LAM), covering most of the North Atlantic with 0.1º resolution. Both models have a spectral discretization of 36 frequencies and 36 directions. IPMA recently implemented the Simulating WAves Nearshore (SWAN) model in the adjacent region to Portugal mainland, with a 0.05º horizontal resolution and a spectral discretization of 36 frequencies and 36 directions.
SWAN is a third-generation wave, developed at Delft University of Technology (TUDelft), Holanda (www.swan.tudelft.nl). At IPMA, SWAN runs over a domain 44ºN/14ºW/36ºN/6ºW, with a horizontal resolution of 0.05ºand a spectral discretization of 36 frequencies and 36 directions. SWAN is forced by the 10 m wind field from the atmospheric limited area model ALADIN (www.cnrm.meteo.fr/aladin/), which runs at IM with 9 km horizontal resolution, and by the spectral density from the European Shelf Model (www.ecmwf.int), which has a horizontal resolution of 0.1º and a spectral discretization of 36 frequencies and 36 directions. The SWAN model predictions are available up to 3 days with a hourly frequency.