On the impact of wind on the development of wave field during storm Britta

The observation of extreme waves at FINO 1 during storm Britta on the 1st November 2006 has initiated a series of research studies regarding the mechanisms behind. The roles of stability and the presence of the open cell structures have been previously investigated but not conclusive. To improve our understanding of these processes, which are essential for a good forecast of similarly important events offshore, this study revisits the development of storm Britta using an atmospheric and wave coupled modeling system, wind and wave measurements from ten stations across the North Sea, cloud images and Synthetic Aperture Radar (SAR) data. It is found here that a standard state-of-the-art model is capable of capturing the important characteristics of a major storm like Britta, including the storm path, storm peak wind speed, the open cells, and peak significant wave height (H s ) for open sea. It was also demonstrated that the impact of the open cells has negligible contribution to the development of extreme H s observed at FINO 1. At the same time, stability alone is not sufficient in explaining the development of extreme H s . The controlling conditions for the development of Britta extreme H s observed at FINO 1 are the persistent strong winds and a long and undisturbed fetch over a long period.