Application Research Of Storm Surges Numerical Simulation Using Unstructured Finite Volume Model In The Bohai Sea And The Changjiang Estuary And Hangzhou Bay

China has a long coastline which will generally have the typhoon invasion leading to the coastal storm surge in the annual summer and autumn season,the Bohai Sea and the Changjiang estuary in China are frequently affected by storm surge.The numerical model can effectively simulate and forecast the generation and development of storm surge,and it can be used to study and reveal the process and law of storm surge on the specific areas coastline invasion.It has the theory and practical significance to protect the economic development of coastal cities and the safety of people's lives and property.Taking into account the sea surface will be forced by the pressure,the wind field when the typhoon occurred,in this paper,based on the three-dimensional unstructured finite volume ocean model(FVCOM),the parameterized typhoon analysis model with pressure field and wind field is added,then a three-dimensional unstructured finite volume storm surge model with astronomical tide,runoff and typhoon is established.This storm surge model is used to simulate and analyze the storm surge in the two typical areas of the Bohai Sea,the Changjiang and Hangzhou Bay estuary.The model uses an unstructured triangular mesh with good fitting ability for the shoreline,and it can better distinguish the effects of near-shore complex nonlinear factors on storm surge.Firstly,the typhoon analysis model is used to simulate the wind speed,wind direction and air pressure drop in the atmospheric forcing,and the results are compared with the wind speed and direction observed in the real typhoon crossing the sea in the history.At the same time,the change of the storm surge in the area under the typhoon is simulated,and the peak data of the storm surge is compared with the measured value,so that the simulated and the measured value on each measured site are in good agreement with each other,and the time series and spatial distribution of the water level in the two coastal areas are analyzed.Secondly,the storm surge model is used to simulate the typhoon storm surge numerical experiments in these areas.The sensitivities of the weather factor,the typhoon path,the coastal and terrain to the storm surge are tested,then these results are compared and analyzed.The ocean physical factors response to the important parameters such as typhoon,shoreline and terrain are discussed,and the response laws of hydrodynamic elements under different typhoon characteristics and shoreline terrain are obtained.