Abstract
Research on drought propagation is of great significance for the scientific prediction of agricultural drought and reducing drought losses. In this study, based on the daily scale standardized precipitation evapotranspiration index (SPEI) and soil water deficit index (SWDI), the effects of irrigation and groundwater level change on the development and spread of drought were studied, and the dynamic change in the spread time from meteorological drought to agricultural drought was explored through a sliding window. Additionally, the critical value of the response of agricultural drought to meteorological drought was calculated. The results indicated that (1) under Scenario-1 (groundwater depth 19.4 m, no irrigation), Scenario-2 (groundwater depth 2 m, no irrigation), and Scenario-3 (groundwater depth 19.4 m, irrigation), the lag times of agricultural drought on meteorological drought were 23 d, 42 d, and 30 d, respectively. (2) The drought propagation time under Scenario-1 and 2 exhibited a significant upwards trend. According to the factor contribution rate and cross-wavelet analysis, the rising trend of the Arctic Oscillation (AO) and the decreasing trend of the Pacific Decade Oscillation (PDO) led to the shortening of sunshine duration, which was the key reason for the extension of drought propagation time. (3) Under Scenario-1, the critical values of the agricultural drought response to meteorological drought duration and intensity were 4.9 and 0.9, respectively. Under Scenario-2, the critical values increased to 5.1 and 2.0, revealing that the propagation of meteorological drought to agricultural drought would slow down when groundwater rose to an appropriate position.
Published Version
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