Estimation of the significant wave height in the nearshore using prediction equations based on the Response Surface Method

Response Surface Method (RSM) is introduced to develop prediction equations in order to estimate nearshore wave height from offshore wave data when the nearshore measurement data were not available or sufficient. The main idea of introducing RSM and developing such prediction equations is to gain a practical and fast estimation of nearshore wave height for a specific region as a substitute for the time-consuming and sophisticated numerical wave model in the case of long-term wave estimation or frequent wave forecasts. A numerical wave model and a semi-analytic fit model derived from the wave energy flux conservation equation were used to fit the response surface of nearshore wave height and develop the prediction equations. The Haitan Strait located in the nearshore area of China East Sea was selected as the studying area. A series of measured wave data obtained from an offshore buoy and 2 nearshore ultrasonic wave gauges from 30th October 2015 to 28th March 2016 were taken as an example. The predictions given by the proposed equations have correlation coefficients of more than 0.85 and root mean square errors of less than 0.19m which are very reasonable when the equations are considered to be concise, efficient and practical.