Propagation mechanisms and triggering probabilities of meteorological to hydrological drought in the Poyang Lake Basin

Study region The middle Yangtze River-Poyang Lake-catchment, China. Study focus This study explores the drought propagation process within the river-lake system of the Poyang Lake basin from 1988 to 2017. Using runs theory, we identified the duration and intensity of meteorological and hydrological droughts. The propagation time from meteorological to hydrological drought was determined through the Pearson maximum correlation coefficient. Using Copula functions, we calculated the probability of meteorological drought triggering river hydrological drought and further analyzed the likelihood of river droughts inducing lake droughts. Furthermore, potential teleconnection factors influencing meteorological drought were explored using methods such as wavelet analysis. New hydrological insights for the region The basin’s meteorological wet-dry state followed a ‘normal-drought-wet’ pattern, entered a drought phase in 2003. While meteorological droughts across the basin averaged 1–2 months, hydrological droughts persisted over 3 months. The Xiushui River experienced significantly more severe hydrological droughts. During drought transmission, as meteorological drought intensifies across the sub-basins, the probability of river drought also increases, Seasonally, the transmission probability was relatively higher during winter-spring. For river-lake transmission Under extreme drought conditions, Xiushui River corresponds to the highest probability of lake drought, Moreover, the probability of lake drought increases as the severity of joint drought across multiple rivers intensifies. Furthermore, compared to AO and PDO, the SOI shows a higher correlation with variations in regional meteorological drought.