the 22nd Pacific−Asian Marginal Seas meeting (PAMS)

Surface flow in the South Pacific plays a key role in regulating heat and tracer transport. Although tropical teleconnections associated with the El Niño–Southern Oscillation (ENSO) are known to influence wind patterns, their impact on wind-driven surface flow has received limited attention. Here, we analyze surface-drifting buoy observations collected during September 2022–May 2023 and November 2023–June 2024 to investigate surface flow in the South Pacific. While drifting eastward, the buoys exhibit pronounced meridional displacements across geostrophic streamlines, indicating the presence of cross-frontal flow. By comparing these observations with wave model outputs, we find that wind wave-driven Stokes drift dominates the surface cross-frontal flow, exceeding the contribution from Ekman velocity. Additionally, the observed cross-frontal flow exhibits distinct interannual variability, which is closely linked to ENSO-driven atmospheric teleconnections. During El Niño periods, anomalous northerly winds generate poleward Stokes drift, enhancing meridional transport. Further analysis suggests the possibility that poleward heat advection driven by wind waves during El Niño periods may contribute to surface warming equivalent to approximately 15% of the atmospheric heat input. These findings highlight a previously underappreciated mechanism through which tropical teleconnections influence extratropical ocean circulation via wind waves. By demonstrating that wind waves can facilitate cross-frontal transport of heat and tracers, this study underscores the importance of incorporating wind-wave processes into climate models to improve projections of future climate variability.
 

Wind waves,ENSO,Surface flow,South Pacific,Stokes drift