波流耦合作用下渤海及北黄海风暴潮增水及海浪过程的数值模拟

本文基于三维波流耦合FVCOM-SWAVE数值模式,采用Jelesnianski参数化风场与再分析数据集ECMWF风场数据叠加而成的合成风场作为外力驱动力,模拟了1818号"温比亚"台风引起北黄海及渤海海域风暴潮增减水及波浪的生长与消减过程,进而分析该海域在"温比亚"台风作用下波浪对流速垂向分布的影响。研究结果表明:合成风场得到的风速最大值及出现时刻与实测数据符合较好,合成风场较为合理,能够为模拟波流耦合机制下海域水动力变化提供准确的风场条件;几个测站的风暴潮增水模拟结果与实测数据较为吻合,FVCOM-SWAVE耦合系统合理地再现了"温比亚"台风在黄渤海引发的风暴潮增水以及台风浪过程。此外,计算结果显示"温比亚"期间黄渤海海域最大有效波高分布于台风中心外围,且位于台风前进方向上,波浪最大有效波高值与台风强度有关;在台风过境期间,波流相互作用对近岸海域流速的垂向分布具有一定影响,考虑波流相互作用可有效提高台风风暴潮数值模拟精度。研究结果对台风灾害预报、防灾减灾及港口建筑选址具有一定的参考意义。

Numerical simulation of storm surge and wave processes in Bohai Sea and North Huanghai Sea under the wave-current interaction

Based on the three-dimensional wave-current coupled model of FVCOM-SWAVE, the total wind field is generated as the external driving force for numerical model coupling the Jelesnianski typhoon model and ECMWF background wind field. The present model is used to simulate the processes of storm surge and wave growth and decay in the North Huanghai Sea and Bohai Sea, and then the vertical distribution of flow current is analyzed during the passage of Typhoon Rumbia. The study results show that the maximum value and occurrence time for wind velocity obtained from the synthetic wind field are in good agreement with the measured data, which verified the reliability of synthetic wind field presented in this study. It can accurately provide the wind field condition for simulating the hydrodynamic change in study area under the wave-current coupling mechanism. Furthermore, the simulated storm surge at several stations agree with the measured data well, showing that the coupled model of FVCOM-SWAVE can reasonably reproduces the storm surge and typhoon wave process caused by Typhoon Rumbia in the Huanghai Sea and Bohai Sea. During the transit period of Typhoon Rumbia, the maximum significant wave height in the Huanghai Sea and Bohai Sea is distributed around the typhoon center and located in the typhoon forward directions, and its maximum value is related to the typhoon intensity. During the passage of the typhoon, the interactions of wave and current have important effect on the vertical distribution of current velocity in the shallow sea areas. The study results have significant reference value for typhoon prediction, disaster prevention and mitigation and port building site selection.