Drought Assessment by a Short-Long-Term Composited Drought Index in the Upper Huaihe River Basin, China

Abstract EN

Accurate and reliable drought monitoring is of primary importance for drought mitigation and reduction of social-ecological vulnerability.

The aim of the paper was to propose a multiscale composited drought index (CDI) which could be widely used for drought monitoring and early warning in China.

In the study, the upper Huaihe River basin above the Xixian gauge station, which has been hit by severe droughts frequently in recent decades, was selected as the case study site.

The newly built short-term/long-term CDI comprehensively considered three natural forms of drought (meteorological, hydrological, and agricultural) by selection of different variables that are related to each drought type.

The short-term/long-term CDI was developed using the Principle Component Analysis of related drought components.

The thresholds of the short-term/long-term CDI were determined according to frequency statistics of different drought indices.

Finally, the feasibility of the two CDI was investigated against the self-calibrating Palmer drought severity index, the standardized precipitation evapotranspiration index, and the historical drought records.

The results revealed that the short-term/long-term CDI could capture the onset, severity, and persistence of drought events very well with the former being better at identifying the dynamic evolution of drought condition and the latter better at judging the changing trend of drought over a long time period.