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arXiv · 1901.05076

Periodicity disruption of a model quasi-biennial oscillation

Antoine Renaud·Louis-Philippe Nadeau·Antoine Venaille
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Abstract

The quasi-biennial oscillation (QBO) of equatorial winds on Earth is the clearest example of the spontaneous emergence of a periodic phenomenon in geophysical fluids. In recent years, observations have revealed intriguing disruptions of this regular behaviour, and different QBO-like regimes have been reported in a variety of systems. Here we show that part of the variability in mean flow reversals can be attributed to the intrinsic dynamics of wave-mean flow interactions in stratified fluids. Using a constant-in-time monochromatic wave forcing, bifurcation diagrams are mapped for a hierarchy of simplified models of the QBO, ranging from a quasilinear model to fully nonlinear simulations. The existence of new bifurcations associated with faster and shallower flow reversals, as well as a quasiperiodic route to chaos are reported in these models. The possibility for periodicity disruptions is investigated by probing the resilience of regular wind reversals to external perturbations.

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BibTeXRIS

Antoine Renaud, Louis-Philippe Nadeau, Antoine Venaille. 2019-01-15. Periodicity disruption of a model quasi-biennial oscillation. https://doi.org/10.1103/physrevlett.122.214504

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