Surface Ocean Warming Around Australia Driven by Interannual Variability and Long-Term Trends in Southern Hemisphere Westerlies

The ocean surface temperature and sea level response around Australia to both interannual variability as well as observed and projected changes in surface winds is presented. A hindcast ocean experiment shows interannual southward shifts in the Southern Hemisphere westerly winds drive ocean surface warming events in the South Australian Basin. Twenty-first century climate and ocean projections in an ensemble of the fifth Coupled Model Intercomparison Project (CMIP5) models show that wind trends could play a role comparable in magnitude to that of radiative warming in driving surface ocean temperature change in this region. To evaluate the wind's role in these projected changes, we use an ocean experiment perturbed by the projected end of 21st century wind anomalies to show that the wind trends alone can generate approximately half of the ocean surface warming and sea level rise predicted by the CMIP5 models in the Tasman Sea.