基于Copula函数法推求分期设计洪水和汛限水位

Seasonal design floods and flood control water levels based on Copula

采用3-维非对称型Frank Copula函数结构,构建汛期分期为三分期、边缘分布为P-Ⅲ型分布的分期洪水联合分布.在假定分期设计洪水值的联合重现期等于防洪标准T的前提下,推导基于Frank Copula函数的分期设计洪水频率和防洪标准的关系,解决了分期设计洪水达不到防洪标准和分期频率与年频率不一致的问题,为分期设计洪水、分期汛限水位优化设计提供了一条新思路.

The triviriate asymmetric Frank Copula is proposed to describe joint distribution of seasonal flood with Pearson Type-Ⅲ distribution margins. When joint return period equals flood prevention standard, the relationship between frequencies of seasonal flood and flood prevention standard is derived; and the inconsistent problem mentioned above is solved. This approach provides a new way to optimize the seasonal design floods and FCWLs.