The SPAR model: A new paradigm for multivariate extremes. Application to joint distributions of metocean variables

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

This paper presents the application of a new multivariate extreme value model for the estimation of metocean variables. The model requires fewer assumptions about the forms of the margins and dependence structure compared to existing approaches, and provides a flexible and rigorous framework for modelling multivariate extremes. The method involves a transformation of variables to polar coordinates. The tail of the radial variable is then modelled using the generalised Pareto distribution, with parameters conditional on angle, providing a natural extension of univariate theory to multivariate problems. The resulting model is referred to as the semi-parametric angular-radial (SPAR) model. We consider the estimation of the joint distributions of (1) wave height and wave period, and (2) wave height and wind speed. We show that the SPAR model provides a good fit to the observations in terms of both the marginal distributions and dependence structures. The use of the SPAR model for estimating long-term extreme responses of offshore structures is discussed, using some simple response functions for floating structures and an offshore wind turbine with monopile foundation. We show that the SPAR model is able to accurately reproduce response distributions, and provides a realistic quantification of uncertainty.

Details

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalJournal of Offshore Mechanics and Arctic Engineering
Volume147
Issue number1
Publication statusPublished - Jul 2024
Peer-reviewedYes

External IDs

Scopus 85205541634