9711号台风对日照近海悬沙浓度影响的数值模拟

Numerical Simulation of the Suspended Sediment Under the Effect of No.9711 Tropic Storm in the Offshore Zone of Rizhao

运用改进的椭圆形风场模型，模拟了9711号台风所经地区风场、气压场的变化过程；将椭圆形风场模型结果结合SWAN波浪模型，计算9711台风过程的波要素；运用COHERENS三维水动力模式，对渤、黄海主要的4个潮分量进行了调和分析，建立渤、黄海天文潮预报模型，并采用三级嵌套模型计算并验证分析了日照近海的水文动力环境；运用基于COHERENS发展的水动力悬沙模型COHERENS-SED，计算分析了9711天气过程、仅考虑潮流作用以及累年平均波要素和一般天气情况（累年平均风场、标准大气压）下的悬沙数值模拟。结果表明：考虑潮流、一般波浪和天气因素共同作用下的水体含沙浓度比仅考虑潮流作用下的水体含沙浓度提高40％～100％的幅度；考虑9711号天气过程以及产生的台风浪作用下的水体含沙浓度比一般波浪和天气因素作用下的水体含沙浓度提高约4倍的幅度。

The wind field and air pressure are simulated successfully with elements of No. 9711 tropic storm by the improved elliptic wind model; Using the wind speed obtained in last process as input data, the wave field of considering area is simulated by SWAN model employing third class nesting. The wave elements （Hs, T et al. ） of No. 9711 tropic storm can be computed; The 3-D COHERENS model is used to carry out analysis of the four principal constituents of astronomic tides （M2, S2, K1, O1） in the Bohai Sea and Yellow Sea. Conse- quently an astronomic tide prediction model for the Bohai Sea and Yellow Sea is established. The hydrodynamic elements are simulated by the established model, and the modeled results of the water surface elevation and current in the offshore area of Rizhao are compared with the measured ones. A 3-D COHERENS-SED model is es- tablished based on the validated COHERENS model. The suspended sediment is simulated under the following three conditions： 1） driven by the No. 9711 tropical storm; 2） driven only by astronomic tides; 3） driven by normal condition （year by year averaged wind elements and the standard air pressure）. The major conclusions of this dissertation are shown as follows： Wind wave plays an important part in the changing the suspended sediment concentration. When the model is driven by both wind and tide, the concentration is much bigger than that only driven by astronomic tides （the increase is about 40 % - 100 % ） especially along the coast.When No. 9711 tropical storm is taken into account, the concentration is 4 times thicker than that under the normal condition.