Copula-based drought risk assessment combined with an integrated index in the Wei River Basin, China

摘要: Abstract It is critical to assess drought risk based on a reliably integrated index incorporating comprehensive information of meteorology, hydrology and agriculture indices, which great value for further understanding the future tendency, prevention mitigation. Thus, primary objective this study was focus constructing multivariate (MIDI) by coupling four indices (i.e., Precipitation Anomaly Percentage (PAP), Runoff (RAP), Standardized Index with 6-month aggregation time step (SPI6) Modified Palmer Drought Severity (MPDSI)) objectively comprehensively investigate risk. The variable fuzzy set theory entropy weight method are used during MIDI construction process. Based MIDI, event including duration severity redefined using run theory. Then copula-based fully assessed through joint probability distribution severity. Results indicate following: (1) constructed consistent (SPI) (RAP) series, it more sensitive effective capture historical events; (2) characteristics present noticeable spatial variability among five subzones, entire basin has 49 droughts longest spanning 8.55 months; (3) mainstream, especially middle lower reaches, higher occurrences severe approximately every 10 years.