抄録
A new system of gradational breaker index is introduced to facilitate the computation of random wave transformations in shallow water. The parabolic equation is used to compute wave shoaling, refraction, and diffraction. Computation is made with multiple levels of wave heights under the Rayleigh distribution. Wave breaking is assumed to occur when the ratio of wave height to local water depth exceeds the breaking index, which takes the largest value for largest wave height level and gradually decreases as the wave height level goes down.
The new system succeeds in reproducing the random wave breaking diagrams by Goda (1975), and shows good agreements with various experimental results on wave transformations over bar and trough topographies, elliptical shoals, and artificial reef systems.
