CHARACTERISTICS OF DIRECTIONAL WAVE SPECTRA ESTIMATED BY A HIGH PRECISION ESTIMATION METHOD OF DIRECTIONAL WAVE SPECTRUM

Abstract

 Directional wave spectra and directional spreading parameter are estimated to investigate properties of wind waves observed in the Sea of Japan in winter season. We estimated directional wave spectra using an estimation method of NIDE proposed by Izumiya et al. The NIDE enabled us to produce high directional resolution even under the different climate condition. The value of directional spreading parameter s observed in the Sea of Japan decrease rapidly as the value of deepwater wave steepness larger than 0. 04 increases. It is also found that the value of s decreases as the wave height increases larger than 4m.