Propagation and future projection of dry-wet abrupt alternation through the hydrological cycle using a GCM-VIC modeling framework

Study region Poyang Lake Basin (PLB), a sub-region of the Yangtze River Basin in Southeast China. Study focus Climate variability and anthropogenic warming have intensified dry-wet abrupt alternation (DWAA) across many regions, posing growing challenges to regional and basin water resources management. However, the propagation patterns of DWAA through the hydrological cycle remain poorly understood. Using ensemble GCM-VIC simulations, the historical and future propagation processes of DWAA were simulated and projected in the PLB. Changes in cropland exposure to soil moisture DWAA were also compared. Propagation characteristics including propagation rate, lag time, and intensity response index were calculated for depicting meteorological-soil moisture DWAA propagation and meteorological-hydrological propagation under both historical and future scenarios. New hydrological insight (1) DWAA frequency and intensity will be higher under the SSP5–8.5 scenario than under SSP2–4.5. (2) Cropland exposure to DWAA events is projected to increase under future climate scenarios, particularly for dry-to-wet transition events. (3) Compared with historical scenarios, delayed propagation times and significant attenuate effects were observed during the DWAA propagation processes, especially under SSP5–8.5 scenario. These findings improve the understanding of DWAA propagation processes, providing useful references for water resource management and reducing risks of hydro-meteorological extremes.