Spatiotemporal variations of meteorological and agricultural drought in the Jitai Basin from 1990 to 2020

【Objective】The Jitai Basin, the second-largest grain-producing basin in Jiangxi Province, is highly vulnerable to drought. Understanding its spatiotemporal drought variations is critical for developing effective mitigation strategies and enhancing water resource management in the region.【Method】The analysis was based on precipitation and potential evapotranspiration data measured from meteorological stations in the basin from 1990 to 2020. These data were used to calculate the monthly, seasonal, and annual Standardized Precipitation Evapotranspiration Index (SPEI). Spatiotemporal variations in SPEI were assessed using the Mann-Kendall trend test. Additionally, the Li Index was calculated, based on crop yield loss due to drought, to evaluate agricultural drought severity. Drought severity was categorized into five levels, and both meteorological and agricultural drought variations were examined.【Result】①From 1990 to 2020, the basin exhibited increasing trends in light to moderate aridity at both monthly (0.000 4/10 a) and annual (0.014 8/10 a) scales, though these trends were not statistically significant. Seasonally, aridity increased in spring (0.029 6/10 a), summer (0.007 9/10 a), and winter (0.007 6/10 a), while autumn showed a significant increasing trend in wetness (0.017 6/10 a). Drought events primarily occurred in summer, autumn, and winter, with no extreme drought events observed in autumn. ② Spatially, Jinggangshan City and Taihe County were the most prone to monthly drought. Anfu County experienced the highest frequency of summer drought, while Suichuan County was most affected by autumn drought. Annually, Anfu County, Jian County, and Jinggangshan City were identified as the most drought-prone regions. ③ The Li Index indicated that the overall frequency of drought events in the Jitai Basin was 67.74%, with moderate droughts accounting for 38.71%. Summer and autumn were most frequently affected by drought, with Ji’an County particularly vulnerable during spring, summer, and winter.【Conclusion】Although drought in the Jitai Basin has shown an increasing trend over the past three decades, the change was not statistically significant. These findings provide valuable insights for developing region-specific strategies to mitigate drought impacts in the basin.