Marine Heatwaves in the East Australian Current Modulated by Mesoscale Eddies

Marine heatwaves (MHWs), defined as periods of persistently elevated ocean temperatures, are investigated along the east coast of Australia. These events are shown to occur as a result of interactions between mesoscale eddies and the East Australian Current (EAC), a poleward flowing western boundary current that transports heat from warmer subtropical seas to cooler temperate latitudes. We show that mesoscale eddies are able to enhance the poleward transport of warm water by the EAC. By reinforcing the southward flow of the EAC, eddies induce strong north-south connectivity during MHW events, with swaths of the shelf and adjacent seas spanning up to 10$°$ of latitude exposed to extreme temperatures simultaneously. The eddy signature of MHWs are detectable by as much as 40 days prior to the peak of any particular event. We discuss the implications of our results as a pathway toward early detection and prediction of extreme ocean conditions in boundary current regions.