Research On Two-dimensional Numerical Modeling Of Extratropical Storm Surge And Inundation And Its Application In Bohai Bay

China is one of the countries that influenced by storm surge badly and most frequently in the world. Storm surges cause serious damage and lost to national defence, industry, agriculture and economy of our country. Through researching on the occurrence, development and attenuation of storm surge to discover the regularity, especially through studying the simulation method to forecast storm surges exactly thus reduce the damage and lost to the lowest extend, is a matter of great significance to China and other countries in the world.In this dissertation the author starts from N-S equation, derives two-dimensional equations of unsteady flow systematically, and establishes two models on basis of that, which are two-dimensional tide numerical model and two-dimensional extratropical storm surge and inundation numerical model. When simulating the storm surge, the author adopts the ADI (Alternating Direction Implicit) Method of finity difference theory to disperse and solve the equations. When simulating the inundation, the author adopts the unstructured grid method of finite volume theory to disperse and solve the equations. The two-dimensional extratropical storm surge and inundation numerical model links these two simulations together and can calculate the storm setup as well as inundation process and area.In this dissertation the author first applies the tide model to the area of Bohai Sea and the north of Huanghai Sea, simulates the tide field and obtains a tide process as boundary condition of storm surge and inundation model. Then applies the two-dimensional extratropical storm surge and inundation numerical model to Bohai Bay, simulates the actual storm surge instance which occurred on 11th~12th October, 2003, and calculates the inundation area.Through the result calculated, we can obtain the information such as time, process, setup of storm surge and inundation area and process, which can be a scientific basis for storm surge forecast for cities along Bohai Bay, and has important meaning for making the surge flood precautionary measures and establishing storm surge mitigation schemes .