Drought Propagation in Mainland China Is More Strongly Associated With Precipitation Partitioning Than With Bulk Precipitation: Historical Patterns and Future Projections

Understanding how meteorological drought propagates to hydrological drought under natural conditions is essential for improving drought early warning, yet the roles of precipitation frequency and intensity in regulating this process remain poorly understood. Here, we quantified drought propagation time (DPT) and drought response rate (DRR) across mainland China under natural conditions, and further assessed the spatial effects of precipitation intensity and frequency using geographically weighted regression (GWR) and future climate projections. The results show that: (a) DRR declines significantly with aridity, with 22.9% of the study area showing DRR values of ≤0.2, indicating weaker meteorological–hydrological coupling in drylands. (b) GWR results indicate that meteorological controls on DPT are dominated by precipitation, while the effects of precipitation intensity and frequency exhibit strong spatial heterogeneity: total precipitation metrics fluctuate around zero across aridity classes, whereas light‐precipitation intensity and heavy‐precipitation frequency are more strongly associated with DPT in drylands, indicating that drought propagation depends more on precipitation partitioning than on bulk precipitation alone. (c) Under future climate scenarios (2030–2100; SSP2‐4.5 and SSP5‐8.5), future changes in drought propagation are driven less by shifts in mean precipitation intensity than by increasing uncertainty in precipitation‐frequency effects, especially in arid and hyper‐arid regions. These findings highlight the critical role of precipitation partitioning in regulating drought propagation and establish a natural‐condition baseline for drought early warning and climate adaptation in water‐limited regions.