The Study To Approximate Solution Of Storm Surge

By using the theoritical analysis, we study the nonlinear interaction between the storm surges and the astronomical tides and the theoritical mode of the storm surges under the control of the wind stress field and the wind pressure field in this paper.The main contents of this paper are divided into four chapters.In chapter one, we introduce the definition of the storm surge and the importance of studying it. The fundamental ideas and methods of this paper are also illuminated in this chapter.In chapter two, a one-dimensional and semi-closed shallow sea mode is studied. The approximate analytical expressions of the water level at the top of the bay induced by the nonlinear interaction between the storm surges and the astronomical tides are obtained by using the perturbation method. Curves of the set-up and water level are offered. The water level is inverse ratio to the average depth of the sea. The nonlinear interation induced tidal period and water level fluctuation obviously. The bottom friction effect is direct ratio to the bottom friction coefficient. The bottom friction effect reduces the set up water level, and minish the set up .In chapter three, We negative the nonliear terms in the system of equations which include surface pressure, wind stress and Coriolis force terms. The height of the storm surge and the storm current can be seen as two terms. One is induced by the wind stress field, another is inducde by the wind pressure field. Then we obtain the height and current of a storm moving along the seacoast at the continental shelf by using Fourier transformation. What Coriolis force contribute to the frequency is analysised later.In chapter four, we make a summary of what we have studied in this paper, then we raise the questions unsolved and will be discussed in the future.