Understanding spatio-temporal patterns of the propagation characteristics across meteorological, hydrological, and agricultural droughts and their influencing factors

Abstract. Understanding the propagation of diverse drought conditions is necessary for drought preparedness. This study conducted a comprehensive analysis of the propagation characteristics across meteorological, hydrological, and agricultural droughts from 1958 to 2024 over global land areas, based on an ensemble of ERA5, GLDAS, and TerraClimate datasets. Using standardized drought indices at different accumulation periods, three drought propagation characteristics, including response time (RT), propagation rate (PR), and lag time (LT), were examined based on time-lag correlation analysis and multi-threshold run theory. The climatic and geographical feature factors that influence drought propagation were quantitatively evaluated using a SHapley Additive exPlanations (SHAP)-based attribution method. The results demonstrate the propagation pathways of meteorological-hydrological-agricultural drought at the global-scale, with the average RT, PR, and LT from meteorological to hydrological 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 hydrological to agricultural drought at 5.8 months, 35.0 %, and 2.49 months, respectively. Notable temporal and spatial heterogeneities are observed in the drought propagation characteristics, which are closely influenced by with the regional climatic feature. Globally, temperature and potential evapotranspiration are the primary factors influencing the propagation of meteorological drought to hydrological drought, whereas precipitation plays a decisive role in the propagation from meteorological or hydrological 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.