The bivariate region frequency extreme value analysis of significant wave height and mean wave period in the South China Sea

Abstract

A comprehensive understanding of extreme significant wave height (SWH) and mean wave period (MWP) benefits greatly the design and construction of offshore structures. In this paper, we present the bivariate region frequency analysis method to spatially investigated the extreme sea state. Based on univariate region frequency analysis approach, this bivariate method provides a chance to combine the similar joint characteristics of extreme sea state conditions at various locations with a specific area. The regional assessment of extreme SWH and MWP is conducted in the South China Sea employing ERA5 wave datasets from 1978 to 2021. Based on multivariate L-moments, the SCS is divided into 35 homogeneity regions which experience discordance test and homogeneity test. The Huangyan Island and Nansha Island near area are chosen to verify the model effect. By comparing the theoretical and empirical density, a series of diagnostic figures indicate the goodness of fit between empirical and theoretical distributions.