Proceedings of the Korea Water Resources Association Conference (한국수자원학회:학술대회논문집)
- 2015.05a
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- Pages.239-239
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- 2015
A bivariate extension of the Hosking and Wallis goodness-of-fit measure for regional distributions
- Kjeldsen, Thomas Rodding (Department of Architecture and Civil Engineering, University of Bath) ;
- Prosdocimi, Ilaria (Centre for Ecology & Hydrology)
- Published : 2015.05.27
Abstract
This study presents a bivariate extension of the goodness-of-fit measure for regional frequency distributions developed by Hosking and Wallis [1993] for use with the method of L-moments. Utilising the approximate joint normal distribution of the regional L-skewness and L-kurtosis, a graphical representation of the confidence region on the L-moment diagram can be constructed as an ellipsoid. Candidate distributions can then be accepted where the corresponding the oretical relationship between the L-skewness and L-kurtosis intersects the confidence region, and the chosen distribution would be the one that minimises the Mahalanobis distance measure. Based on a set of Monte Carlo simulations it is demonstrated that the new bivariate measure generally selects the true population distribution more frequently than the original method. An R-code implementation of the method is available for download free-of-charge from the GitHub code depository and will be demonstrated on a case study of annual maximum series of peak flow data from a homogeneous region in Italy.