Understanding meteorological, runoff, and agricultural drought propagation and their influencing factors in an ensemble of multiple datasets

Understanding the propagation of diverse drought conditions is essential for effective drought preparedness. This study evaluated the propagation of meteorological, runoff, and agricultural droughts across global land areas from 1958 to 2024 using an ensemble of reanalysis data (ERA5), land surface model simulations (GLDAS), and merged observational datasets (TerraClimate). Two distinct methodological frameworks were employed to characterize drought propagation: time-lag correlation analysis and multi-threshold run theory. Based on standardized drought indices derived from precipitation, runoff, and soil moisture, the drought propagation characteristics of response time (RT), propagation rate (PR), and lag time (LT) were examined. Moreover, the climatic and geographical factors influencing drought propagation were quantified using the SHapley Additive exPlanations (SHAP)-based attribution method. The results demonstrate the propagation pathways of meteorological-runoff-agricultural drought at the global scale, with the average RT, PR, and LT from meteorological to runoff drought at 5.0 months, 55.3 %, and 1.23 months; from meteorological to agricultural drought at 8.7 months, 30.3 %, and 2.60 months; and from runoff to agricultural drought at 5.8 months, 35.0 %, and 2.49 months, respectively. Drought propagation exhibits pronounced spatiotemporal heterogeneity, closely related to the regional climatic background. Temperature and potential evapotranspiration are the primary factors influencing the propagation of meteorological drought to runoff drought, whereas precipitation plays a decisive role in the propagation from meteorological or runoff drought to agricultural drought. The findings underscore the importance of taking climatic characteristics into account in the development and implementation of regional drought risk management.