On the spectrum width of wind waves

Based on the universal expression of wind wave spectra, four commonly used definitions of the spectrum width are re-examined. The results show that th e non-dimensional spectrum width can measure the width of non-dimensional s pectra but it does not reflect the developing state of the spectra. The dim ensional spectrum width expresses the degree of concentration of wave energ y of the spectrum in the process of wind wave growth. Tests show that the s pectrum width presented by Wen et al. can objectively measure the degree of concentration of wave energy of the spectrum, reflect the state of wind wa ve growth, and provides a better result for practical application, The rule s for definition of the spectrum width are discussed.