A Forecast Model Of Storm Surge Inundation With High Resolution

China is among the countries suffering severely from oceanic disasters that threaten not only the development of coastal economy, but also the safety of human life. Among the oceanic disasters, storm surge ranks first because of its relatively high frequency and severe damages. So it is important to study and forecast storm surge.In order to forecast the storm surge inundation, a two-dimensional forecast model of storm surge inundation is established. In the model, an alternating computation sequence method is used to solve the governing equations. And the dry and wet method is introduced to treat the moving boundary. The dry and wet model can be used for complex topography. Moreover, the original fixed boundary numerical scheme can be easily transformed to a moving boundary model by introducing additional part, dealing with the dry and wet points. But this kind of treatment is invalid according to the fluid dynamics theory. Although the coordinate transformation model can overcome this defect, it is difficult to be used in a complex topography. So the dry and wet method is used here because of the complex shoreline of Shantou.In this model, three nested areas are used, two of which are with input from the large areas, interpolated in space and time along its open boundaries. In order to fully consider the influence of the typhoon, the big area is taken as large as possible. So three areas are nested to make the connection more reasonable. The result of the big area is the storm surge elevation while the result of the small area is the total elevation.The model is applied to Shantou and the storm surge inundations caused by typhoon 6903, 7908,8607,9107 and 0104 are simulated to obtain the storm surge elevations and the ranges of storm surge inundation. According to the model result,the comparisons between the computed storm surge elevations and observed ones are got. And from the figures we can see the simulated results agree with those of observed except at the stations to the south of the typhoon center. The reason is that the actual wind field is more complex than our model wind field and may consist other atmospheric systems. The storm surge inundation is displayed by Arc View GIS. And the inundation range is in accordance with the actual result.With the development of both computer science and data acquisition techniques, increasing attention is being paid to the operational numerical forecast model. Our forecast model of storm surge inundation is aimed at operational forecast. After selecting of a proper area, information about the topography (including ocean terrain and land elevation) of the area and tidal conditions along the open boundary are inputted into the computer, and the forecast model will then be run. The typhoon data, such as the longitude and latitude of the typhoon center, the radius of Beaufort scale 7 wind, the maximum wind velocity, the air pressure in the typhoon center and the time the typhoon started and ended are also inputted into the computer to get the results of the storm surge inundation. The variation process of the storm surge elevation can be dynamically displayed through Matlab. And through Arc View GIS, all information of the inundation areas will be output statistically.Certainly, there is shortage in our model. On one hand, we can use the wind field calculated by the atmospheric model such as MM5; on the other hand, the ArcView GIS is to be developed to add the inquired function.