Pacific Basin Wind-Wave Models: The Generation and Propagation of Low Frequency Energy

An overview of global wave modeling methods currently used by the U.S. Navy is presented, and the advantages and disadvantages of various approaches are discussed. Two Pacific Basin swell events are presented for illustration, one typical of winter events at the California coast, the other typical of summer swells. The WAM model performs poorly in both cases. Model underprediction of wave generation is the primary source of error for the winter swell, while wave propagation errors explain the poor performance for the summer swell. A new approach for reducing error associated with propagation is proposed. Test results for a canonical case are discussed.