Intensified Western Boundary Currents in South China Sea Under Global Warming

Abstract The upper‐layer western boundary currents (WBCs) in the South China Sea (SCS) play a crucial role in regulating ocean dynamics, marine ecosystems, and regional climate. However, due to limited observations and coarse model resolution, changes in these currents on centennial timescales remain unclear. This study investigates trends in upper‐layer circulation in the SCS from 1951 to 2050 using outputs from an ensemble of 16 high‐resolution climate model members. Under global warming, the WBCs exhibit strengthening in both winter and summer, with a 7.7% increase (0.60 ± 0.47 Sv) in the winter Vietnam Coastal Current (VCC) and an 8.5% increase (1.10 ± 0.55 Sv) in the summer Vietnam Offshore Current (VOC) over the study period. Further analysis using a 1.5‐layer reduced‐gravity model suggests that enhanced stratification drives the intensification of the VCC in winter while the strengthening of the VOC in summer is primarily modulated by increased stratification and partially influenced by the intensified local wind stress curl. The results of this study may serve as a foundation for further research on the ecological effects caused by enhanced WBCs of the SCS.