Spatio‐temporal characterization of Korean drought using severity–area–duration curve analysis

Abstract

AbstractIn this study, the depth–area–duration (DAD) analysis for characterizing an extreme precipitation event provides a basis for analysing drought events when storm depth is replaced by an appropriate measure of drought severity. Monthly precipitation is probabilistically transformed into standardized precipitation index (SPI) and SPI time series are decomposed into a mutually independent data set by the empirical orthogonal function (EOF) analysis. All EOFs are spatially expanded to a 6 × 6 km resolution by kriging, for which a commercial package, SuRFER™, is used. Twenty main drought events from the grid‐based SPI time series are identified to construct the drought severity–effective area–drought duration (SAD) curves. The shape of SAD curves is similar to that of the rainfall DAD curves in the sense that drought severity and effective area are out of phase and that drought severity and duration are also out of phase. However, the severity reduction rate in SAD curves is much smaller than the corresponding rate in DAD analysis.