Journal article
Improved Extreme Rainfall Frequency Analysis Using a Two-Step Kappa Approach
D O’Shea, R Nathan, A Sharma, C Wasko
Water Resources Research | Published : 2023
DOI: 10.1029/2021WR031854
Open access
Abstract
Accurate estimation of annual exceedance probabilities (AEPs) of extreme rainfalls through rainfall frequency analysis is a critical step in engineering design for flood mitigation and disaster response. Here we show how the estimation of rainfall frequency curves can be improved by fitting a four-parameter Kappa distribution to a peaks-over-threshold (POT) series. To fit the Kappa distribution to POT data we present a two-step fitting approach based on maximum likelihood estimation which separately models storm intensity and the arrival frequency. First, a Generalized Pareto distribution (GPA) describing storm intensity is fitted, followed by a Binomial distribution for storm arrivals. We c..
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Grants
Awarded by Australian Research Council
Funding Acknowledgements
The authors would like to acknowledge conversations with George Kuczera and Melvin Schaefer which helped inform the initial ideas for this paper. The authors are also grateful for the many thoughtful and constructive comments provided by the reviewers which greatly helped shape the final form of the article. Declan O'Shea acknowledges the support of an Australian Government Research Training Program Scholarship and the University of Melbourne Lochrie Engineering Scholarship. Conrad Wasko acknowledges funding from the Australian Research Council (ARC) DE210100479. This research was supported by the ARC Discovery project DP200101326 and by industry support from Hydro Tasmania, Melbourne Water, Murray-Darling Basin Authority, Queensland Department of Regional Development Manufacturing and Water, Seqwater, Snowy Hydro, Sunwater, West Australia Water Corporation, and WaterNSW. Open access publishing facilitated by The University of Melbourne, as part of the Wiley - The University of Melbourne agreement via the Council of Australian University Librarians.