舟山海域风暴潮特征及数值模拟研究

Study on characteristics and numerical simulation of storm surge around the Zhoushan Island

选择20个对舟山海域有较大影响的历史台风案例,开展定海站实测潮位数据的分析与归纳,总结得出20个台风中风暴潮过程增水最大值为5612号台风的207.1cm,风暴潮高潮位最大值为9711号台风的283.7cm。同时,在三维斜压水动力模型SELFE的基础上加入台风气压场和风场模块,建立了一个采用非结构三角形网格的天文潮-风暴潮耦合模型,模拟表明定海站的斜压效应较为明显,非线性耦合作用相对较弱,但两潮耦合风暴潮增水结果仍优于风暴潮单因子增水结果,与实际增水更为接近。在此基础上,以一定间隔在5612号台风原路径南北两侧各设计了2条平行路径,分别模拟两潮耦合风暴潮增水,结果表明5612号台风参数沿其原路径偏南1个最大风速半径距离的S1路径运动时可模拟得到定海站可能最大风暴潮增水为243.9cm。最后,在S1路径下模拟可能最大风暴潮增水分别遭遇天文高、中、低潮位时的风暴潮高潮位,结果表明天文潮高潮时可得到可能最大风暴潮高潮位约为400cm,天文中潮时次之,而天文低潮时风暴潮高潮位最低。

Twenty historical typhoons which had a great impact on the Zhoushan sea area,were selected to perform analyses and inductions of the measured tidal level data at Dinghai station.It was found that in these twenty typhoons,the maximum storm surge was 207.1cm under the Typhoon 5612,and the maximum storm high tidal level was 283.7cm under the Typhoon 9711.Further,a 3D baroclinic hydrodynamics model,SELFE,was used to establish an unstructured triangular grid astronomical tide-storm surge coupled model,through adding the typhoon pressure field and wind field modules.The numerical results show that the baroclinic effect is more obvious while the nonlinear coupling is relatively weaker.But the two-tides-coupled storm surge data are still better than the single-factor data and closer to the measured data.On this basis,in the north and south of the original path of the Typhoon 5612,two parallel paths at certain intervals were designed respectively. The corresponding results show that the supposed typhoon which adopts the parameters of the Typhoon 5612 and moves along the S1 parallel path in the south of the original typhoon path at a distance interval of a maximum wind radius,can induce the probable maximum storm surge of approximately 243.9cm.Finally,supposing that the probable maximum storm surge separately encounters the astronomical high,middle or low tidal level,it is found that there appears a probable maximum storm high tidal level of about 400 cm when encountering the astronomical high tide.