Dynamical changes in the ENSO system in the last 11,000 years
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A thorough analysis of a proxy El Nino/Southern Oscillation (ENSO) record indicates that a bifurcation occurred in the ENSO system sometime around 5,000 years b.p. As a result of this bifurcation the attractor became higher dimensional and a new mechanism of instability was introduced. As a consequence of these changes the system switched from a dynamics where the normal condition (La Nina) was dominant to a dynamics characterized by more frequent and stronger El Nino events.
KeywordsENSO Climate variability Chaos Bifurcation
I thank the students in my spring 2008 class “nonlinear time series analysis” for helping me with the production of some of the figures used here.
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