Characteristics of meteorological-hydrological drought propagation in the Yangtze River Basin: dynamic and spatiotemporal variations, 2003–2022

Studying drought propagation is crucial as it enables us to gain a more profound understanding of the scope and magnitude of drought impacts and to accurately monitor the evolving dynamics of droughts. We conducted an in-depth examination of the propagation characteristics of meteorological and hydrological droughts in the Yangtze River Basin (YRB) spanning from 2003 to 2022. The results demonstrate that, during the study period, the meteorological and hydrological droughts in the YRB have exhibited an increasing trend. Specifically, the time it takes for a meteorological drought to propagate into a hydrological drought is 7 months. The sensitivity and propagation response rate are 25% and 50%, respectively. The propagation times in spring and summer are significantly shorter. Furthermore, the study reveals a consistent decreasing trend in the drought propagation response rates and speeds across the entire region. Conversely, the propagation time is increasing at a rate of 0.36 months per year.