基于Copula函数的设计潮位过程要素组合风险分析

Risk Probability Analysis of Element Combination in Design Tide Process Based on Copula Function

现行推求设计潮位过程大多采用高潮位与潮差同频率放大的方法,未考虑到二者遭遇可能性的大小。采用G-H Copula函数建立了年最高潮位和相应潮差的二维联合分布模型,通过组合风险分析法研究了设计高潮位和设计潮差的组合风险率。以天津港多年实测资料计算分析为例,结果表明:较大重现期的高潮位和潮差同时发生的概率较小,50年一遇高潮位与50年一遇潮差组合的风险率仅为0.05%,同频率设计偏安全,可依据组合风险率适当降低潮差设计标准。所采用的联合分布模型及其应用,在定量分析基础上为设计潮位过程的推求提供了一种新方法。

The method with high tidal level and tidal range being enlarged by the same design frequency is widely used in the derivation of design tide process at present. By using G-H Copula function, a two-dimensional joint distribution of annual maximum tidal level and its corresponding tidal range was built. Thereafter, the risk probability of the combination of design high tidal level and design tidal range was studied. Long-term observations on Tianjin Port were analyzed and the results indicate that the probability is low when extreme high tidal level encountering high tidal range, the combination risk probability of high tidal level with 50-year return period and tidal range with 50-year return period is 0.05%, the results calculated through enlarging the elements by the same frequency were performed safer, the design criteria of tidal range can be reduced properly according to the risk probability. The joint distribution model and its application provide a new method for deriving design tide process on the basis of quantitative analysis.