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.

Automated summary

A new inter-basin teleconnection analysis method is proposed to investigate the connection among global oceans comprehensively. The Australia Boundary Current Dipole (ABCD) is discovered, which shows a strong negative correlation between sea surface temperature (SST) along Leeuwin Current (LC) and East Australia Current (EAC). This new inter-basin air-sea coupled mode exhibits remarkable interannual variability. The anomalies in SST are mainly generated by anomalous Australia High inducing opposite surface winds along the coast, which in turn reinforce the wind anomalies by affecting the overlying atmosphere and 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.