Study on the Characteristics and Propagation Law of Hydrological Agricultural Drought in Henan Yellow River Water Supply Area

ABSTRACT To relieve droughts and supply demand imbalances in Henan Yellow River water supply area and improve water security, this study focuses on the drought evolution characteristics at different times and spaces. Standardized runoff index (SRI) and standardized soil moisture index (SSMI) were selected to characterize hydrological and agricultural drought. Based on Arc GIS and Mann–Kendall trend test method, this study revealed the temporal and spatial variation characteristics of drought trend at the hydrological and agricultural levels. The Gray Relational Analysis method is used to analyze the correlation degree between SRI and SSMI at different scales. The Pearson correlation coefficient and sliding window method are used to assess the correlation between multi scale SRI and monthly scale SSMI sequences and the seasonal changes in drought propagation time. The results of the study demonstrate that: (1) Hydrological drought in Henan Yellow River water supply area is generally moderate or severe in spring and winter, it is mainly mild or nonexistent in summer and autumn; (2) Agricultural drought of mild severity or above is primarily concentrated in the central‐eastern regions; (3) The overall drought propagation time from hydrological to agricultural drought is 6 months. The optimal drought propagation times for the four seasons are 2, 1, 2, and 4 months. This study enabling early implementation of drought emergency prevention and control measures.