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

Moussa Ndour, Kathrin Padberg-Gehle, Martin Rasmussen
2021 Fluids  
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
more » ... erator 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.
doi:10.3390/fluids6020049 fatcat:qjo277nexrgqhih2v7glg5drcq