The Southern Annular Mode (SAM), the leading mode of atmospheric variability in the Southern Hemisphere, profoundly influences extratropical–subtropical climate interactions. The subtropical Southeast Pacific (SSEP) is a critical region of strong ocean–atmosphere coupling and extensive stratocumulus cloud decks, where sea surface temperature (SST) anomalies significantly impact the global energy balance. However, the mechanisms by which SAM modulates SSEP SST remain inadequately understood.
This study investigates the pathways through which SAM drives SSEP SST variability. Our results reveal two dominant processes: First, SAM-induced surface wind anomalies alter latent heat flux via the wind–evaporation–SST (WES) feedback, whereby intensified southeasterlies enhance evaporation and cool the sea surface. Second, SAM reorganizes the large-scale Hadley and Ferrel circulations, generating pronounced subsidence over the SSEP. This adjustment features lower-tropospheric easterlies, upper-level westerlies, and a vertical wind shear structure that reinforces descending motion. The enhanced subsidence reduces low-level cloud cover, thereby increasing shortwave radiation at the surface and amplifying the initial SST anomalies.
These findings underscore the pivotal role of SAM in regulating SSEP SST through coupled dynamical and thermodynamical pathways, advancing our understanding of extratropical–subtropical teleconnections in the Southern Hemisphere climate system.

Southern Annular Mode (SAM); Subtropical Southeast Pacific SST; Wind–Evaporation–SST feedback; Hadley–Ferrel circulation; Low-cloud radiative