Bivariate drought frequency curves and confidence intervals: a case study using monthly rainfall generation
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Although water resources management practices recently use bivariate distribution functions to assess drought severity and its frequency, the lack of systematic measurements is the major hindrance in achieving quantitative results. This study aims to suggest a statistical scheme for the bivariate drought frequency analysis to provide comprehensive and consistent drought severities using observed rainfalls and their uncertainty using synthesized rainfalls. First, this study developed a multi-variate regression model to generate synthetic monthly rainfalls using climate variables as causative variables. The causative variables were generated to preserve their correlations using copula functions. This study then focused on constructing bivariate drought frequency curves using bivariate kernel functions and estimating their confidence intervals from 1,000 likely replica sets of drought frequency curves. The confidence intervals achieved in this study may be useful for making a comprehensive drought management plan through providing feasible ranges of drought severity.
KeywordsDrought Frequency Confidence interval Copulas
This work was supported by Grants from Korean National Research Foundation (No. 2010-0016717) and Korean National Emergency Management Agency (NEMA-11-NH-40). The authors also thank the anonymous reviewers for their constructive comments and corrections.
- Chen L, Singh VP, Gui S (2011) Drought analysis based on copulas. 2011 Symposium on data-driven approaches to droughts. Purdue University, West LafayetteGoogle Scholar
- Oliveria JDT (1975) Bivariate extremes: extensions. Bull Int Stat Inst 46(2):241–251Google Scholar
- Sharma A, O’Neill R (2002) A nonparametric approach for representing interannual dependence in monthly streamflow sequences. Water Resour Res 38(7): 5–1:5-10Google Scholar
- Silverman BW (1986) Density estimation for statistics and data analysis. Chapman & Hall/CRC, LondonGoogle Scholar
- Sklar A (1959) Fonctions de repartition a n dimensions et leurs marges. Publ Inst Statist Univ Paris 8(1):11Google Scholar
- Wilhite DA (2000) Drought as a natural hazard: concepts and definitions. Drought A Global Assess 1:3–18Google Scholar
- Yevjevich V (1967) Objective approach to definitions and investigations of continental hydrologic droughts. Hydrology Paper 23, Colorado State U, Fort CollinsGoogle Scholar