Interplay between the Indonesian Throughflow and the Luzon Strait Throughflow

Abstract

Analysis based on the “Island Rule” and ocean assimilation dataset shows that the interannual variability of the Indonesian Throughflow and the Luzon Strait (South China Sea) Throughflow is out of phase. Wind anomaly in the equatorial Pacific plays an important role in setting up this phase relation. During El Niño events, the westerly wind bursts intensify the Northern Equator Current and induce a northward shift of its bifurcation point. As a result, the partition of volume transport between the Kuroshio and the Mindanao Current is changed, with the Kuroshio transport decreased and the Mindanao Current increased. The undershooting/overshooting phenomena occur at the Luzon Strait and the Sulawesi-Mindanao passage, caused by variability of these two currents. Water transport from the Pacific to the South China Sea increases with the Kuroshio transport decreased, and transport from the Pacific to the Indian Ocean decreases with the Mindanao Current transport increased. Therefore, the interannual variability of the Indonesian Throughflow and the Luzon Strait Throughflow is out of phase.