Impacts of Intermediate Water Formation in the North Pacific on Indonesian Throughflow and Equatorial Thermocline Depth: A High Latitude Control for ENSO Variability?

Abstract

Long-term variability in the strength and frequency of the El Niño - Southern Oscillation (ENSO) may be attributable to changes in background climatology. During times of cold climate events in the high latitudes, El Niño conditions may have been more persistent in the equatorial Pacific. In this study, a numerical ocean model was used to examine the role oceanic circulation may play in linking these two regions. The simulation of an intermediate body of water of 10 Sv in the North Pacific results in an overall decrease in flow of 29% across the Indonesian Seaways. No change in the overall structure of the thermocline was observed; however the model predicted warming of the surface water in the western and eastern tropical Pacific. It is, therefore hypothesized that a sinking water mass in the North Pacific could have fueled either more permanent El Niño - like conditions or more frequent/intense ENSO events.