Joint distribution of wave periods and rate of change of wave surface elevation

The rate of change of wave surface elevation is of much importance in ocean engineering, especially for the determination of the limitation of wave br eaking. This paper gives a kind of joint distribution of wave periods and t he rate of change of wave surface elevation by means of calculation of the two-order to four-order moment of the frequency spectrum based on the linea r wave theory. For the first time, the distribution density function of wav e periods determined by peaks is provided, and the conclusion is drawn that the rate of change of wave surface elevation obeys the Rayleigh distributi on.