Climate Network-Based Synchronized Structures Identification of Extreme Droughts and Pluvials in Cross-basin Regions

Global warming has intensified the frequency of synchronous extreme climate events, posing severe threats to the water-food-energy-ecosystem nexus and challenging regional sustainability. Current studies overlook the inverse symbiotic relationship of the droughts and wet events and the complex, nonlinear spatiotemporal correlations underlying transregional extreme climate events. Here, using complex network, we systematically identify the synchronous structure of drought, pluvial, and drought–pluvial dipole (DPD) events within the Western Route of the South-to-North Water Diversion Project in China. Our analysis reveals a distinct wet-dry co-variability between the Yangtze and Yellow River basins. From the perspectives of atmospheric circulation and local weather systems, we elucidate the physical coupling between extreme hydroclimatic events and circulation anomalies as well as moisture transport pathways. We identify remote coupling zones of DPD events and highlight a pronounced spatial asymmetry in cross-basin hydroclimatic behavior. Drought and pluvial synchronicity is predominantly characterized by short-to-medium spatial scales, compared to DPD events exhibiting robust cross-basin teleconnections. Notably, the signal sources for these extremes are anchored in the southwestern portion of the study area. We show that positive geopotential height anomalies, airflow subsidence, and monsoon disruption drive drought conditions, whereas the transport of warm, moist air generates pluvial events -together forming a “drought-pluvial seesaw” at the climatic scale. This study provides critical scientific foundation for cross-basin water resource management and offer vital insights for developing climate-resilient infrastructure and optimizing adaptive spatial planning under a changing climate.