Ocean current signals propagation along the Outer Banda Arcs

Abstract

Equatorial Pacific Rossby waves may enter into the interior of the Indonesian Throughflow (ITF)’s eastern pathway, such as along the Outer Banda Arcs (OBA). This study aimed to investigate the dynamics of the ITF along the OBA channel from Ceram Sea to Aru Basin to Western Timor Passage. This is necessary because it can provide information about the physical oceanographic conditions, especially the dynamics of the current in the study area. Based on the Hovmoller diagram, a propagation of the signal from kinetic energy was found along the OBA which its phase speed theoretically appears to be trapped in Rossby waves, because of the similarity of the speed phase. The normal mode analysis shows that the oscillation in Ceram Sea, Aru Basin, and Timor Passage has the same pattern based on the potential density and Brunt-Vaisala frequency profiles. The transport’s coherence between Indo-Pacific meridional winds and transport volume in Aru Basin shows a strong coherence value (0.94) which is dominated by an annual variability with a period of 341 days. The results suggest that zonal winds along the equator Pacific Ocean act as a remotely forced Rossby waves that propagate westward, entering the interior of Indonesian Seas.