Extraction of wave height-period joint probability distribution from empirical frequency spectrum

Frequency spectra obtained from the wave height and period joint probability distribution function (H-T JPDF) yields results that differ from the widely used empirical frequency spectrum. Thus, Accordingly, this study proposed a method to obtain H-T JPDF by combining the wave height distribution for each period adopted from the theoretical equations of Longuet-Higgins and Cavanie et al. and the empirical frequency spectrum. Consequently, waveforms were generated from the empirical spectrum and then compared with the H-T JPDF obtained by zero-up crossing method to validate the proposed methodology. The validity of the proposed JPDF was evaluated through comparisons of wave data observed in shallow coastal areas at Gonghyunjin in the eastern coast and Heukdo in the western coast of Korea having completely different wave environments. In addition, the validity of the theoretical probability distribution of wave height was investigated by comparing it with observed wave data.