Xueying Wang: Responses of the subtropical gyres and subtropical mode waters to tropical wind intensification
The ocean absorbs more than 90% of excess anthropogenic heat, playing a central role in regulating the global climate. Subtropical gyres are key components of the global ocean circulation and are strongly influenced by tropical wind variability. Although observations indicate that tropical winds have intensified since the 1980s, the impacts on subtropical heat uptake and subtropical mode water (STMW) variations remain unclear. Here, we conduct idealized experiments using ACCESS-OM2-025, where tropical winds are intensified by 10%, 20%, and 30% over a 50-year period to investigate the link between tropical wind forcing and subtropical heat storage. We find that enhanced tropical winds strengthen the mean circulation, driving increased ocean heat advection from the tropics to the subtropics through western boundary currents. This wind intensification also enhances STMW formation and its associated heat uptake, increasing subsurface heat storage in both the subtropical and global oceans. These findings identify a mechanism linking tropical wind intensification to subtropical ocean heat storage, highlighting the role of tropical winds and subtropical mode waters in regulating ocean heat accumulation under global warming.