Agricultural drought mitigating indices derived from the changes in drought characteristics

Abstract

Droughts can cause tremendous losses to agricultural and economic development; humans have explored many anti-drought measures to mitigate the influence of drought and accordingly altering the characteristics of actual agricultural drought. In this study, a method is proposed to detect the spatiotemporal changes in drought characteristics, which show the effects of anti-drought measures on drought mitigation. Two agricultural drought mitigation evaluation indices are proposed, the agricultural drought frequency change (ADFC) and agricultural drought area change (ADAC), which are calculated by combining the Palmer drought severity index (PDSI) and vegetation health index (VHI), two widely used drought monitoring indices. The PDSI and VHI represent the natural and actual agricultural drought severity under natural and actual conditions respectively, and their differences in drought frequency and affected area reflect the level of anti-drought measures in mitigating agricultural drought. The feasibility of using ADFC and ADAC to quantify the effects of anti-drought measures for agriculture is explored using data from six typical agricultural provinces in the North China Plain and Northeast China. The results show that ADFC and ADAC could reflect both the spatiotemporal changes in agricultural drought characteristics and the influence of anti-drought measures on agricultural drought. The trend of the drought mitigation index is consistent with agricultural activity statistics. These two indices could be further used to evaluate the effects of different anti-drought methods and aid in defeating agricultural drought across many countries.