Numerical Simulation Of Typhoon-generated Waves For Chengmai Bay Of Hainan Island

Typhoons and tropical storms have severe impacts on the region of the south to south-east coast of China every year.In order to provide basis for coastal structure design and protection,it is of great significance to update the design wave parameters and storm surge because in recent years super typhoons occur with higher and higher frequency.A typhoon process is related with three major aspects: weather condition,waves and currents.These three parts interact with each other,which significantly affects the calculation results.Firstly,the WRF mesoscale atmospheric model was adopted to simulate 33 typhoons that had significant influence on Hainan Island from 1999 to 2018,and the data of wind field and pressure field during the typhoon were obtained.Through calibration,the central paths of typhoon and the maximum wind speeds during each typhoon are in good agreement with the measured data,which verifies the applicability of the WRF model.Secondly,the SWAN wind wave model and ADCIRC shallow water wave model are coupled to simulate the wave and storm surge caused by each typhoon.The simulation results of wave and water level setup are in good agreement with the measured data.Based on the analysis of the variation process of wave and setup in the Macun sea area during Typhoon Rammasun,it is found that the wave height on the right side of the typhoon's forward direction is obviously higher than that on the left side.Based on the simulated wave height and period data,the joint probability distribution relationship between wave height and period during typhoon is studied.It is found that Zheng Guizhen model can accurately describe the wave height periodic distribution in Chengmai Bay.Finally,based on the 20-year wave and storm surge process data obtained from numerical simulation,the wave elements and storm surge results at the depth of-20 m outside Macun Port are extracted,and the wave parameters are determined by curve-fitting approach using the Pearson III cumulative frequency curve,and the recurrence period of storm surge in the coast near Macun Port is analyzed.