Numerical Simulation Of Storm Surge And Wave In The Northern South China Sea Based On Parametric Wind Field

When a typhoon occurs,it will be accompanied by a strong low-pressure cyclone,which will cause secondary storms such as huge storm surges and typhoon waves.The Leizhou Bay area in the northern part of the South China Sea is one of the largest storm surge occurrence areas in China.The maximum water increase can reach 5.5m and the effective wave height can reach 12 m.Therefore,it is of great significance to simulate the storm surge and typhoon waves in the northern part of the South China Sea.In the numerical simulation study of storm surge and typhoon wave,the simulation accuracy is affected by the typhoon chlorine pressure field and the accuracy of the wind field.The wind speed and the wind speed required for the simulation calculation of the typhoon wave must be input through the wind field mode.Choosing the appropriate typhoon pressure field and wind field,given accurate input data,is crucial in the numerical simulation study of storm tidal storms.Based on historical typhoon observation data,this paper studies the calculation models and key parameters of typhoon wind and pressure fields in the southeastern seas of China,and carries out numerical simulations of storm surges and typhoons in the northern South China Sea,and analyzes the typhoon crossings in the South China Sea.The characteristics of maximum water increase and maximum wave height distribution under storm surge.The research content and results of this paper are as follows:1)Based on the Holland model pressure field and wind field,the empirical formula between the maximum wind speed Vm and the maximum wind speed radius Rmw is given by analyzing the parameter samples of the JTWC typhoon optimal path data set.2)According to the typhoon wind field gradient equation,the Holland parameter B is fitted,and the experience of the Holland B coefficient between the radius r,the wind speed V(r)at any radius,the typhoon center latitude ? and the typhoon center air pressure difference ?p is given.Relationship.Then the model is compared with five Holland B empirical calculation models.After statistical analysis and error analysis,the Holland B parameter calculation model suitable for the southeastern seas of China is selected.3)Calculate the sample of Holland parameter B according to the model and give its spatial distribution map in the southeastern seas of China.The results show that under the empirical model calculation,the spatial distribution of Holland parameter B has obvious regional differences,in the east longitude.In the range of 105°~120°,the value of Holland B is mostly between 0.7 and 1.0.In the range of 120°~140° east longitude,the value of Holland B is mostly between 0.9 and 1.2.The result from the spatial distribution map In view of it,it also shows that the value of Holland B in the range of 120°~140° east longitude is larger.4)According to the coupling pattern of typhoon field,wave and storm surge,a coupling model of the South China Sea astronomical tide and storm surge and wave based on parametric wind field is established.The representative 1415 "Seagull" typhoon is selected.Based on the calculation model of the optimal Holland parameter B found in this paper,the key parameters of the typhoon wind field pressure field in the model are determined.The verification shows that the established storm surge,astronomical wave and wave coupling numerical simulation have higher precision,and the storm surge water increase and wave wave height process are consistent with the measured results.5)Analyzed the characteristics of maximum water increase and maximum wave height distribution under the action of storm surge during the typhoon crossing.The maximum water increase in the eastern part of Leizhou Peninsula is greater than the maximum water increase in the Qiongzhou Strait.The water in the eastern part of Leizhou Peninsula is increased by more than 3m.The maximum water increase is in the waters of Leizhou Bay.The maximum water increase is above 5.5m,and the western part of Leizhou Peninsula appears.More than 2m of water reduction.Influenced by the shallow water depth in the eastern part of the Leizhou Peninsula,the maximum effective wave height of the Qiongzhou Strait is higher than that of the eastern part of the Leizhou Peninsula,but it is lower than the outer sea of the eastern part of the Leizhou Peninsula.The effective wave of the outer sea of the eastern part of the Leizhou Peninsula can be as high as 12 m.It can also be as high as 6.5~7.5m.