Spectral Properties of Cyclone-Generated Waves in Deep and Shallow Water

Juan is recorded as one of the most damaging storms in the modern history of Nova Scotia, Canada. In this paper, the spectral evolution characteristics of waves generated by hurricane Juan are studied, based on the observed 1D wave spectra along Juan’s track in deep open ocean waters (buoy 44137) and the 2D wave spectra in shallow coastal waters at the directional waverider (DWR) location. Valuable results are obtained for cyclone-generated wave spectral properties, in both deep and shallow waters. In deep water, as illustrated at buoy 44137, the spectral variation, spectra pattern development, spectral peak frequency, cut-off frequency coefficient and high frequency spectral tail of the wave spectra are analyzed, before, during and after the cyclone’s passing. Thus, the spectral variation characteristics during the entire cyclone processe are obtained. Properties of the high frequency spectral tail are discussed, using average frequency and peak frequency as the cut-off frequency parameters under different cut-off coefficient conditions, respectively. We suggest reasonable values for the cut-off frequency parameter. Cyclone-generated 2D wave spectra in shallow water (at DWR location) are investigated, shoaling effects, 2D spectral pattern variations, swell and wind waves spectral evolution. Our study shows the invalidity of presently accepted spectral formulae, in describing cyclone-generated waves.