Chen, Lu; Singh, Vijay P; Guo, Shenglian - 2011
. Using monthly standardized Precipitation Index (SPI) values, drought characteristics, namely, drought duration, severity …, interval time and minimum SPI values, were determined. Two exponential distributions were used to model drought duration and … model minimum SPI value. Several copulas in the Archimedean and meta-elliptical families were applied to construct four …