ONA-ENS, the multimodel sea wave prediction system of the SMC

In Catalonia, with around 580 km of coast, most of the population living in the littoral and a lot of socioeconomic activities relying on the sea, accurate wave prediction is essential. The Meteorological Service of Catalonia (SMC) plays a critical role in issuing warnings to the authorities and the population to mitigate potential risks associated with the sea state. Due to the intrinsic uncertainty of the wave models and the probabilistic nature of the early warnings, an Ensemble Prediction System (EPS) is of great help, if not mandatory, to issue these early warnings.  

ONA-ENS (multimOdel oceaN wAve Ensemble for the catalaN coaSt) is the multimodel and multiphysics sea wave EPS developed in the SMC for the Balear-Catalan Sea, in the western Mediterranean. It uses the two spectral wave models that are already running in the SMC, SWAN and WW3. In order to take into account the model uncertainty, each model is run with three different parameterizations of the generation and dissipation of the waves. In addition, the initial conditions uncertainty is introduced by using two atmospheric global models, IFS and GFS, that initialize two configurations of the regional model WRF. These atmospheric models produce the wind fields that drive the wave models. Thus, there are four atmospheric members that initialize six wave configurations, creating a 24-member sea wave ensemble. The system is run every day at 00 UTC, with hourly time steps up to five days, at a 3 km spatial resolution.  

Here we share the verification results of the ONA-ENS using the data obtained from the 7 buoys of Puertos del Estado available in the Balear-Catalan Sea during 2023. Comparisons against the deterministic operational models at the SMC reveal a reduction in bias. From a probabilistic point of view, comparisons with the ENS ECWAM from ECMWF show an improvement in the dispersion for the first days of the forecast.