Extreme Wave Height Events in NW Spain: A Combined Multi-Sensor and Model Approach

TLDR

The Galician coast in NW Spain experiences severe sea states driven by mid‑Atlantic low‑pressure systems and periodic storms. The study aims to (1) characterize the most extreme winter wave height events (2015‑2016) using high‑frequency radar data and IBI‑WAV forecasts, and (2) demonstrate the use of satellite wave altimetry for daily skill assessment of the IBI‑WAV model. The authors combined high‑frequency radar measurements with IBI‑WAV predictions and employed satellite three‑hourly wave height estimates, focusing on monitoring Hurricane Ophelia’s 3‑day track over Ireland and the UK. The results confirm that IBI‑WAV forecasts are highly accurate and that integrating observations with modeling yields a comprehensive characterization of severe coastal wave conditions, highlighting the complementary strengths of both systems.

Abstract

The Galician coast (NW Spain) is a region that is strongly influenced by the presence of low pressure systems in the mid-Atlantic Ocean and the periodic passage of storms that give rise to severe sea states. Since its wave climate is one of the most energetic in Europe, the objectives of this paper were twofold. The first objective was to characterize the most extreme wave height events in Galicia over the wintertime of a two-year period (2015–2016) by using reliable high-frequency radar wave parameters in concert with predictions from a regional wave (WAV) forecasting system running operationally in the Iberia-Biscay-Ireland (IBI) area, denominatedIBI-WAV. The second objective was to showcase the application of satellite wave altimetry (in particular, remote-sensed three-hourly wave height estimations) for the daily skill assessment of the IBI-WAV model product. Special attention was focused on monitoring Ophelia—one of the major hurricanes on record in the easternmost Atlantic—during its 3-day track over Ireland and the UK (15–17 October 2017). Overall, the results reveal the significant accuracy of IBI-WAV forecasts and prove that a combined observational and modeling approach can provide a comprehensive characterization of severe wave conditions in coastal areas and shows the benefits from the complementary nature of both systems.