Surface wave simulation during winter with sea ice in the Bohai Sea

Sea ice can attenuate wave energy significantly when waves propagate through ice covers. In this study, a third-generation wave model called simulating wave nearshore (SWAN) was advanced to include damping of wave energy due to friction in the boundary layer below the ice. With the addition of an eddy viscosity wave-ice model, the resulting new SWAN model was applied to simulate wave height in the Bohai Sea during the freezing winter. Its performance was validated with available buoy data near the ice edge, and the new model showed an improvement in accuracy because it considered the ice effect on waves. We then performed a wave hindcast for the Bohai Sea during a freezing period in the winter of 2016 that had the severest ice conditions in recent years and found that the mean significant wave height changed by approximately 16.52%. In the Liaodong Bay, where sea ice concentration is highest, the change reached 32.57%, compared with the most recent SWAN model version. The average influence of sea ice on wave height simulation was also evaluated over a five-year (2013-2017) hindcast during January and February. We found that the wave height decrease was more significant in storm conditions even the eddy viscosity wave-ice model itself showed no advantage on damping stronger waves.