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Bivariate flood frequency analysis using the copula function: a case study of the Litija station on the Sava River
Author(s) -
Sraj Mojca,
Bezak Nejc,
Brilly Mitja
Publication year - 2014
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.10145
Subject(s) - bivariate analysis , copula (linguistics) , flood myth , environmental science , hydrology (agriculture) , frequency analysis , statistics , geology , mathematics , geography , econometrics , geotechnical engineering , archaeology
As an alternative to the commonly used univariate flood frequency analysis, copula frequency analysis can be used. In this study, 58 flood events at the Litija gauging station on the Sava River in Slovenia were analysed, selected based on annual maximum discharge values. Corresponding hydrograph volumes and durations were considered. Different bivariate copulas from three families were applied and compared using different statistical, graphical and upper tail dependence tests. The parameters of the copulas were estimated using the method of moments with the inversion of Kendall's tau. The Gumbel–Hougaard copula was selected as the most appropriate for the pair of peak discharge and hydrograph volume ( Q‐V ). The same copula was also selected for the pair hydrograph volume and duration ( V‐D ), and the Student‐t copula was selected for the pair of peak discharge and hydrograph duration ( Q‐D ). The differences among most of the applied copulas were not significant. Different primary, secondary and conditional return periods were calculated and compared, and some relationships among them were obtained. Copyright © 2014 John Wiley & Sons, Ltd.