A nonlinear model for nonbreaking shoaling random waves

In this paper,the spatial evolution of the third-order moment (i.e.,the skewness) of the sea surface elevalion for nonbreaking shoaling random waves versus H_s/d is analyzed by using the data obtained in field and laboratory. Using the empirical relationship given in this paper, the nonlinear model for the sea surlace elevation of nonbreaking shoaling waves in the sernnd-order approximation by expanding the first two terms of Hermitian polynomial is depicted by the parameter H_s/d, and such characteristics as the power spectrum, the bispectrum and the distribution function of sea surface elevation es well have been derived in this paper. The correlation between the skewness and the kurtosis of the sea surface elevation is also discussed.