Multi-modal excitation to model the Quasi-Biennial Oscillation

Abstract

The Quasi-Biennial Oscillation (QBO) of stratospheric winds is the most striking example of mean-flow generation and reversal by the non-linear interactions of internal waves. Previous studies have used an idealized monochromatic forcing to investigate the QBO. Here we instead force a more realistic continuous wave spectrum. Unexpectedly, spreading the wave energy across a wide frequency range leads to more regular oscillations. We also find that different forcing spectra can yield the same QBO. Multi-modal wave forcing is thus essential for understanding wave/mean-flow interactions in nature.

arXiv commentMain text: 6 pages, 4 figures. Supplemental: 7 pages, 5 figures. To be published in Physical Review Letters

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Cited by in corpus (1)

• A self-consistent numerical model of internal wave-induced mean flow oscillations in polar geometry