Research On Numerical Calculation Model Of Extratropical Storm Surge And Application In Bohai Bay

Storm surge is one of the most serious disasters in all of the oceanic disasters, and China is one of the countries that influenced by storm surge disaster and frequently occurred in the world. It causes serious damage and lost to national defence, industry, agriculture and economy. Therefore, studying the storm surge numerical methods and improving the precision of storm surge forecast have urgent and practical significance.A brief analysis of the characteristics of storm surge and its influence on coastal areas was presented in this paper, and summarized the progress of storm surge studies. Based on the basic equation of three-dimensional flow, the two-dimensional and three-dimensional storm surge mathematical model equations were derived. The ADI (Alternating Direction Implicit Method) difference scheme of finite difference method was applied in the discretizing and solving the governing equations. Considering the influence of the astronomical tide and wind stress to the storm surge, the two-dimensional and three-dimensional numerical model of extratropical storm surge were established. Quasi-three-dimensional was applied in the numerical model of three-dimensional, and then non-planar depth division model and planar equal depth distribution model were introduced. The two different models's result was compared, and the characteristics of the two models were analysed.Based on the conditions of actual ocean region, the computational region was divided into large model and small model in this paper. The large model covered the area of Yellow Sea and Bohai Sea, and the small model covered the Bohai Bay. The two-dimensional and three-dimensional numerical model were applied to the large model and small model, and then a storm surge which occurred in Yellow Sea and Bohai Sea on 8 th - 10 th May, 2009 were simulated. Two cases were considered in the numerical simulation, which were adding wind stress only in small model and adding wind stress in both model. Using the observation data of Tanggu tidal station, the calculation results of strom surge tidal level and storm surge setup were verified. About the verification results, the storm surge setup of the two-dimensional numerical model was good agreement with the measured data in the case of adding wind stress only in small model, the calculation results of depth layered method were better than depth isometry layered method in the three-dimensional numerical model.