Comparison of the positive and negative Indian Ocean Dipole forcing on the Pacific interannual variability through the oceanic channel

Numerical experiments using a regional ocean–atmosphere coupled general circulation model show the influence of Indian Ocean Dipole (IOD) events on the Pacific Ocean through the oceanic channel known as the Indonesian Throughflow (ITF) by isolating the role of the atmospheric bridge. The 2019 Positive IOD and 2016 Negative IOD events can force enhanced and decreased ITF transport through subsurface processes. Currents and sea level anomalies allowed a thorough comparison between 2016 and 2019 IOD events. The upwelling and downwelling Kelvin waves can propagate through the Indonesian seas along the Sumatra–Java island chain, forcing SSHA in the southeastern basin to grow quickly and reach the western Pacific Ocean. The numerical results suggest that the 2016 negative IOD could cause an El Nino-like state and that the 2019 positive IOD could cause a La Nina-like state in the Pacific Ocean.