Contributions of Indo‐Pacific Forcings to Interannual Variability of the Indonesian Throughflow in the Upper and Lower Layers

Abstract

AbstractThe paper uses reanalysis data and model outputs to quantify relative contributions of the El Niño‐Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) to the vertical structure variability of the Indonesian Throughflow (ITF) using multiple regression analysis. In comparing ENSO to IOD events, it becomes evident that ENSO plays a more significant role in ITF upper layer (0–300 m) transport, while the IOD has a greater impact on ITF lower layer (300–760 m) transport. Given the larger anomaly in ITF upper layer transport, ENSO dominates the interannual variability of ITF transport. Moreover, ITF transport is influenced by different physical processes associated with varying phases of ENSO and the IOD. The month‐by‐month contributions reveal that the IOD primarily controls ITF transport during El Niño development years, while ENSO has more influence during El Niño decaying years.