Assimilation of HF radar data into the SWAN wave model

Data assimilation is a method used for optimally combining information to improve forecasting and model parameters. Three data assimilation algorithms are investigated and used for assimilating HF radar data into the SWAN wave model. The schemes under consideration are the Ensemble Kalman Filter, Ensemble Optimal Interpolation and a Three-Dimensional Variational scheme. Two approaches for updating the ocean wave spectrum are considered which consist of describing the spectrum using integral wave parameters of the whole spectrum and wave parameters within various frequency bands. The results show improvement in the wave parameters at the buoy location for the 3DVAR and ENS-OI scheme. The EnKF only shows good performance in one of the considered runs which leads to a conclusion that the methods used for calculating the errors for the EnKF scheme need further analysis.