Nonlinear excitation of zonal flows by rossby wave turbulence

Mendonça, J T and Shukla, P K and Bingham, R (2009) Nonlinear excitation of zonal flows by rossby wave turbulence. New Journal of Physics, 11. 073038. ISSN 1367-2630

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    Abstract

    We apply the wave-kinetic approach to study nonlinearly coupled Rossby wave-zonal flow fluid turbulence in a two-dimensional rotating fluid. Specifically, we consider for the first time nonlinear excitations of zonal flows by a broad spectrum of Rossby wave turbulence. Short-wavelength Rossby waves are described here as a fluid of quasi-particles, and are referred to as the 'Rossbyons'. It is shown that Reynolds stresses of Rossbyons can generate large-scale zonal flows. The result should be useful in understanding the origin of large-scale planetary and near-Earth atmospheric circulations. It also provides an example of a turbulent wave background driving a coherent structure.