Maintaining a dynamic equilibrium in river–lake relationships is crucial for mitigating the impacts of climate change and enhancing water resources security. Future climate change can threaten this equilibrium by enabling the propagation of meteorological drought into hydrological drought within a lake watershed. However, future climate projections introduce substantial uncertainties into the quantification of drought propagation. In this study, we focus on China’s largest freshwater lake, the Poyang Lake Basin, to investigate the propagation characteristics of projected meteorological-to-hydrological droughts. We first applied the Equidistant Cumulative Distribution Function (EDCDF) method to correct biases in climate projections, then elucidated the future characteristics of meteorological-to-hydrological drought propagation using standardized drought indices. Results show that (1) the EDCDF can significantly reduce uncertainties in climate projections, with improvement of the Kling-Gupta Efficiency ( KGE ) by 12.2 ± 13.8% and reduced bias by 7.72 ± 10.3%. (2) Projected meteorological droughts will become less frequent (-5%) but more severe (+ 60%), while hydrological droughts will be characterized by higher frequency (+ 50%), lower severity (-8.2%), and shorter duration (-3%). These significant divergences indicate the nonlinear evolution of meteorological-to-hydrological droughts. (3) Future drought propagation time will shorten by 47.5%, with response rates near unity and severity ratios below 1, indicating stronger coupling yet persistent attenuation of drought signals. Our findings highlight the increasing risk to river basin sustainability and the urgent need for improving drought forecasting and management.
Xie et al. (Sun,) studied this question.