Discovery of a New Inter‐Basin Climate Pattern: Australia Boundary Current Dipole

A new inter‐basin teleconnection analysis method is proposed to comprehensively investigate the connection among global oceans. The strong negative correlation (−0.59) between sea surface temperature (SST) along Leeuwin Current (LC) and East Australia Current (EAC) is discovered and named as Australia Boundary Current Dipole (ABCD). This new inter‐basin air‐sea coupled mode exhibits remarkable interannual variability, with a peak phase in austral summer. The related SST anomalies are mainly generated by anomalous Australia High induced opposite alongshore surface winds to enhance/suppress the heat transport of the two warm currents, in turn, reinforce the wind anomalies by heating/cooling the overlying atmosphere and changing regional pressure anomalies. The meridional ocean advections control the anomalous SST, indicating the essential role of coastal Bjerknes feedback. The kinetic energy analysis further demonstrates that ABCD represents the reverse variation pattern of LC and EAC. Plain Language Summary The interactions between different oceans have strong impact on the global climate change. We proposed a new method aims to reveal global oceans interactions and thus discovered the opposite change features between the sea surface temperature (SST) off the west and east coasts of Australia. The coastal SST anomalies are accompanied by the synchronous evolution of alongshore surface winds, coastal boundary currents, and sea level pressure, demonstrating it as an intervein climate pattern and we name it as Australia Boundary Current Dipole (ABCD). The anomalous Australia High, evaporation anomalies and the heat transport of Leeuwin Current (LC) and East Australia Current (EAC) contribute to the evolution of ABCD. ABCD also indicates reverse variability of LC and EAC. Our results reveal the existence and generation mechanism of ABCD for the first time, which advances our knowledge of air‐sea interactions and may provide new insights into the research of marine ecology. Key Points A new method is proposed to reveal inter‐basin teleconnection A new inter‐basin climate pattern between Indian and Pacific Oceans is discovered and named Australia Boundary Current Dipole (ABCD) ABCD represents the reverse variability feature of Leeuwin Current and East Australia Current