Multivariate hydrological frequency analysis using copulas

TLDR

The study models multivariate extreme values with copulas. The authors applied the copula methodology to two hydrological problems: combined risk in frequency analysis and joint modeling of peak flows and volumes. The copula approach enables dependence modeling independent of marginals, and tests on Peribonka and Rimouski watersheds show promising results by capturing diverse correlations.

Abstract

This article presents the modeling of multivariate extreme values using copulas. Our approach allows us to model the dependence structure independently of the marginal distributions, which is not possible with standard classical methods. The methodology has been applied on two different problems in hydrology. The first application is concerned with the combined risk in the framework of frequency analysis. Four copulas have been tested on peak flows from the watershed of Peribonka in Québec, Canada. The second application relates to the joint modeling of peak flows and volumes. Three copulas have been applied to the watershed of the Rimouski River in Québec, Canada. This approach using copulas is promising since it allows us to take into account a wide range of correlation which can happen in hydrology.