Evaluation of drought severity based on regional drought characterization

Abstract

Drought is a recurring natural phenomenon represented by severity, duration, and areal extent. Multidimensional characteristics of a drought make univariate analysis unable to reveal the significant relationship among drought properties. Furthermore, historical records tend to be too short to fully evaluate drought characteristics. Therefore, this study is proposed to estimate the bivariate return period of droughts based on the use of regionalized data to evaluate the drought severity. The Standard Precipitation Index (SPI) is used to represent the drought states in Korea. After extracting drought properties using the SPI time series at each gauging station, the drought properties are regionalized based on discordancy and heterogeneity measures verified the grouping precipitation observatory by the cluster analysis. The regionalized drought properties are used for the bivariate drought frequency analysis to evaluate the severity of historical droughts in Korea. The method proposed in this study may be useful in drought mitigation plan through evaluating drought severities based on bivariate drought return period, as well as in understanding of regional and statistical behavior of droughts beyond the limitation of the univariate frequency analysis.