The importance of being chaotic: Bifurcations in an El Niño model
Held by Andrew Keane (University of Auckland, New
09.05.2017, 16:00 Uhr
We consider a conceptual model for the El Niño Southern Oscillation system, where the delayed effects of energy transport across the Pacific Ocean are incorporated explicitly into the model, which gives a description by a delay differential equation. We conduct a bifurcation analysis of the model by means of dedicated continuation software, which allows us to find regions of different types of solutions in the parameter space. In this way, we determine how the observed dynamics is influenced by changing certain parameters of the model. Our bifurcation analysis demonstrates that the irregular nature of El Niño events can be reproduced by chaotic behaviour resulting from the interplay between delayed feedback and seasonal forcing. It also uncovers the phenomenon of folding invariant tori, which may be interpreted as a form of climate tipping.