In order to describe the overall drought status objectively, a copula-based joint deficit index (JDI) was adopted for analyses of drought characteristics in Luanhe River basin. Monthly precipitation data from 1958 to 2011 selected from 26 rain-gauge stations were used for calculating the JDI. The JDI, which encompasses multiple deficit status over the time scales from 1 to 12 months by using the 12-dimensional empirical copula, is shown to be capable of providing a comprehensive and objective assessment of droughts. In addition, it is demonstrated that both emerging and prolonged droughts can be captured by the JDI. Results of the drought evaluation over the Luanhe River basin indicate that the frequency of drought occurrence generally increases from northwest to southeast, and droughts observed in summer and autumn are more frequent and severe. Compared with the northwestern part of the area, the drought events in the southeast are characterized by longer duration and greater severity. Furthermore, a general tendency of drying is found in the flood season (July to September) over the basin, with significant aggravating trends in the southeastern part. These related drought characteristics could provide valuable information and references for regional mitigation strategies and water resource management.
- drought characteristics
- joint deficit index
- standardized precipitation index
- First received 14 July 2015.
- Accepted in revised form 24 October 2015.
- © IWA Publishing 2015