The Impact of Subtropical to Tropical Oceanic Interactions on Tropical Pacific Decadal Variability

Slow natural variations of the tropical Pacific Ocean have a worldwide climatic impact which motivates understanding and predicting this low-frequency variability. The Pacific subtropical cells (STCs), an ocean circulation that connects the subtropics to the tropics in each hemisphere, have been proposed to drive such slow variations. In this thesis, we closely analyse different physical mechanisms by which the STCs can act as a driver. We show that variations in the strength of the Southern hemisphere STC as well as the equatorward transport of density compensated temperature anomalies by both STCs play a dominant role in inducing low-frequency variability.