Copula-based risk assessment of drought in Yunnan province, China

Yunnan is one of the provinces which had been frequently and heavily affected by drought disasters in China. Recently, large severe droughts struck Yunnan, caused considerable social, economic and ecological losses. A risk assessment of meteorological drought for Yunnan province is provided in this study. Based on the daily meteorological data of 29 stations during 1960-2010, duration and severity as two major drought characteristics, defined by the runs and the composite meteorological drought index, are abstracted from the observed drought events. Three bivariate Archimedean copulas are employed to construct the joint distributions of the drought characteristics. Based on the error analysis and tail dependence coefficient, the Gumbel-Hougaard copula is selected to analyze spatial distributions of the joint return periods of drought. The results indicate that a high risk is observed in the middle parts and the northeast parts of Yunnan province, while a relative lower drought risk is observed in the northwest of Yunnan province. The probabilistic properties can provide useful information for water resources planning and management.