Tropical Indo‐Pacific Teleconnections to Southern Ocean Mixed Layer Variability

Abstract

AbstractThe Southern Ocean plays a fundamental role in the global energy and carbon budgets via the uptake of large quantities of heat and carbon in subantarctic mode water (SAMW). Even though SAMW variability is closely tied to variations in mixed layer depth (MLD) and properties, little is known about what controls interannual to multidecadal MLD variations. Here we use atmospheric observations combined with a global 1/10° ocean‐sea ice model to examine the mechanisms controlling Southern Ocean mixed layer variability. We find that tropical teleconnections from the Indo‐Pacific to the Amundsen Sea Low via El Niño–Southern Oscillation and the Indian Ocean Dipole control mixed layer variability along the path of a Rossby wave train across the South Pacific during early winter. This suggests recent multidecadal variations in mixed layer properties are likely to have been significantly impacted by transitions in the Interdecadal Pacific Oscillation.