Observed ENSO teleconnections to Southern Ocean SST anomalies diagnosed from a surface mixed layer heat budget

Abstract

This study examines the mechanisms that govern the El Niño Southern Oscillation (ENSO) teleconnections to variability in extratropical Southern Hemisphere sea surface temperature (SST) anomalies using several observational and reanalysis products. During the warm season, turbulent heat fluxes and heat advection by Ekman currents contribute equally to ENSO‐related SST variability throughout the Southern Ocean, while shortwave radiation has a larger contribution in the subtropics. A comparison of the ocean mixed layer heat budget between multiple re‐analysis products reveals that the relative contributions of the turbulent, radiative and Ekman heat fluxes to ENSO‐related SST anomalies is consistent between the NCEP, ERA‐40 and OAFlux/ISCCP products, but discrepancies exist with regard to the structure and amplitude of the turbulent heat fluxes and, to a lesser extent, the shortwave radiation. However, a comparison between the tendencies in SST and flux‐derived temperatures reveals minimal residuals, suggesting that the ENSO‐signal in the SST field can be resolved by turbulent, Ekman, and radiative heat fluxes, particularly in the ERA‐40 products.