杭州湾内风暴潮与天文潮的耦合效应

Interaction Between Storm Surge and Astronomical Tide in Hangzhou Bay

研究杭州湾内风暴潮和天文潮之间的相互复杂作用对于准确预报风暴潮增水有着重要的意义.本文采用ADCIRC垂向积分水动力数学模式和藤田台风模型,计算风暴潮与天文潮耦合作用下的潮位过程,并与简单线性叠加的结果进行比较,探讨理想条件下天文潮与风暴潮的非线性作用特征.同时对杭州湾地区的天文潮以及9711号典型台风过程引起的风暴潮进行计算,分析该地区天文潮和风暴潮之间的非线性作用特征及影响因素.结果均表明,天文潮影响下的风暴潮增水过程存在与天文潮相同周期性波动成分;和耦合计算相比,简单叠加得到的水位有高估高潮位、低估低潮位的趋势.

The nonlinear interaction between storm surge and astronomical tide is of significant importance to predicting water level during a storm. In this study, the ADCIRC model and Fujita typhoon model were used to compute the water level during a storm with storm surge and astronomical tide. The result was compared with the linear superposition of astronomical tide and the storm surge without tide effects. By comparing the results of the coupling computation and the linear superposition, the characteristics of nonlinear interaction between storm surge and astronomical tide were obtained under an ideal condition. The model was also applied on Hangzhou Bay. The astronomical tide and storm surge caused by the No. 9711 typhoon were studied and the results agreed well with the field data. Further analysis showed that the characteristic of the interaction effects in Hangzhou bay was similar with that obtained under the ideal condition. The results showed that the storm surge fluctuates in the same period with astronomical tide due to the influence of tide. It was also found that the highest water level would be overestimated and the lowest water level would be underestimated by the linear superposition of astronomical tide and storm surge without considering their interaction effects.