Spectral Early-Warning Signals for Sudden Changes in Time-Dependent Flow Patterns

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Lagrangian coherent sets are known to crucially determine transport and mixing processes in non-autonomous flows. Prominent examples include vortices and jets in geophysical fluid flows. Coherent sets can be identified computationally by a probabilistic transfer-operator-based approach within a set-oriented numerical framework. Here, we study sudden changes in flow patterns that correspond to bifurcations of coherent sets. Significant changes in the spectral properties of a numerical transfer operator are heuristically related to critical events in the phase space of a time-dependent system. The transfer operator approach is applied to different example systems of increasing complexity. In particular, we study the 2002 splitting event of the Antarctic polar vortex.

Original languageEnglish
Article number49
Issue number2
Number of pages24
Publication statusPublished - 02.2021

Bibliographical note

Funding Information:
Funding: This research has received funding from the European Union’s Horizon 2020 Research and Innovation Program under the Marie Sklodowska-Curie grant agreement No. 643073 (ITN CRITICS) as well as from the Deutsche Forschungsgemeinschaft within the Priority Program SPP 1881 Turbulent Superstructures (PA1972/3-2).

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

    Research areas

  • Lagrangian transport, bifurcation, coherent set, probabilistic approach, singular value decomposition, transfer operator
  • Mathematics