台风作用下风-浪-潮三维环境等值面模型

ENVIRONMENTAL CONTOUR OF WIND-WAVE-STORM SURGES INDUCED BY TYPHOONS

  • 摘要: 台风登陆时常伴随强风、巨浪和风暴潮,如何获取台风下的风、浪、潮数据并确定给定重现期下的环境参数成为制约跨海桥梁设计的关键科学问题。以跨海桥梁众多的舟山海域为例,采用SWAN+ADCIRC耦合模型,对过去32年间影响该海域的49次台风过程依次开展数值模拟,利用模拟出的台风作用下风、浪、潮参数建立100年重现期下的环境等值面,讨论了环境参数选取方法对环境等值面模型的影响。研究表明:该文建立的数值模型能为后期构建联合概率及环境等值面模型提供可靠的数据来源;三维嵌套Frank Copula能较好拟合风-浪-潮三维联合概率分布;给定重现期的环境等值面形状受数据选取时刻影响较大,其中风暴潮增水最大值对选取方法最为敏感。

     

    Abstract: Typhoons usually induce strong winds, huge waves and storm surges when they make landfall. The acquisition of data of the typhoon-generated winds, waves, and storm surges and the determination of the corresponding environmental design parameters with a given return period are two critical issues that restrict the design of sea-crossing bridges. Taking Zhoushan sea area where many sea-crossing bridges are located as an example, a SWAN+ADCIRC coupling model was employed to simulate the metocean conditions under typhoons. Hindcast simulations of 49 typhoons that affected the example site in the past 32 years were conducted. The environmental contours with a 100-year return period were calculated using the simulated winds, waves and storm surges. The influence of the data selection on the environmental contours was investigated. The results show that: The numerical model employed in this study can provide reliable data for developing joint probability and environmental contour models; The nested three-dimensional Copula well fits the trivariate joint probability distribution of typhoon-induced winds, waves and storm surges. The environmental contours with a given return period depend on the data selection method, and the maximum storm surge is the most sensitive parameter to this factor.

     

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