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An Organizing Center for Thermohaline Excitability

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  • 1 Leibniz-Institute of Marine Science (IfM-Geomar), University of Kiel, Kiel, Germany
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Abstract

The bifurcation behavior of a conceptual heat–salt oscillator model is analyzed by means of numerical continuation methods. A global (homoclinic) bifurcation acts as an organizing center for the dynamics of the simplified convective model. It originates from a codimension-2 bifurcation in an extended parameter space. Comparison with earlier work by Cessi shows that the intriguing stochastic thermohaline excitability can be understood from the bifurcation structure of the model. It is argued that global bifurcations may play a crucial role in determining long-term variability of the thermohaline circulation.

Corresponding author address: Dr. Jan Abshagen, Ocean Circulation and Climate/Theory and Modelling, Leibniz-Institute of Marine Science, University of Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany. Email: jabshagen@ifm-geomar.de

Abstract

The bifurcation behavior of a conceptual heat–salt oscillator model is analyzed by means of numerical continuation methods. A global (homoclinic) bifurcation acts as an organizing center for the dynamics of the simplified convective model. It originates from a codimension-2 bifurcation in an extended parameter space. Comparison with earlier work by Cessi shows that the intriguing stochastic thermohaline excitability can be understood from the bifurcation structure of the model. It is argued that global bifurcations may play a crucial role in determining long-term variability of the thermohaline circulation.

Corresponding author address: Dr. Jan Abshagen, Ocean Circulation and Climate/Theory and Modelling, Leibniz-Institute of Marine Science, University of Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany. Email: jabshagen@ifm-geomar.de

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