Spectral Early-Warning Signals for Sudden Changes in Time-Dependent Flow Patterns
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In: Fluids, Vol. 6, No. 2, 49, 02.2021.
Research output: Journal contributions › Journal articles › Research › peer-review
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TY - JOUR
T1 - Spectral Early-Warning Signals for Sudden Changes in Time-Dependent Flow Patterns
AU - Ndour, Moussa
AU - Padberg-Gehle, Kathrin
AU - Rasmussen, Martin
N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/2
Y1 - 2021/2
N2 - 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.
AB - 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.
KW - Lagrangian transport
KW - bifurcation
KW - coherent set
KW - probabilistic approach
KW - singular value decomposition
KW - transfer operator
KW - Mathematics
UR - http://www.scopus.com/inward/record.url?scp=85104399176&partnerID=8YFLogxK
U2 - 10.3390/fluids6020049
DO - 10.3390/fluids6020049
M3 - Journal articles
VL - 6
JO - Fluids
JF - Fluids
SN - 2311-5521
IS - 2
M1 - 49
ER -