An Operational Method for Separating Wind Sea and Swell from Ocean Wave Spectra*

Coexistence of wind sea generated locally and swell radiated from distant storms often results in double-peaked or multiple-peaked spectra. Identification and separation of the wave energies of wind sea and swell provide a more realistic description of the sea state, which is of great importance to scientific and engineering applications. This paper describes a method based on the peak frequency of a newly defined steepness function to separate the wave energies of wind sea and swell from the omnidirectional wave spectra. This steepness method does not rely on the availability of the information of wind velocities and wave directions and can be easily implemented for operational uses. Verification results using directional wave data collected from buoys in the Gulf of Mexico and offshore California are presented.