Response of Antarctic Circumpolar Current Jets to Southern Hemisphere Westerly Shifts During the 21st Century

Abstract The Antarctic Circumpolar Current (ACC) is strongly influenced by the Southern Hemisphere Westerly winds (SHW), which is projected to intensify and shift poleward under increasing anthropogenic radiative forcing. However, the extent of ACC frontal jet responses to these changes remains uncertain. Using simulations from two CMIP6 (Coupled Model Intercomparison Project Phase 6) models (GFDL‐CM4 and HadGEM3‐GC31‐MM) under the SSP5‐8.5 (Shared Socioeconomic Pathway) scenario, we analyze ACC jet displacements. Our results reveal spatially heterogeneous shifts, with the most pronounced changes in the southeastern Indian Ocean, particularly along the 110°E–120°E sector, where weaker topographic constraints allow for greater jet mobility. In contrast, minimal displacements occur in the South Pacific and South Atlantic, despite substantial SHW shifts. These findings suggest that topographic anchoring is the dominant regulator of ACC frontal jet positioning in a warming climate while localized exceptions highlight the complexity of jet–topography interactions.