Nonlinear Radiating Instability of a Barotropic Eastern Boundary Current
Name
Wang-2013-Nonlinear radiating.pdf
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1.27 MB
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Author(s)
Wang, Jinbo
Spall, Michael A.
Flierl, Glenn Richard
Rizzoli, Paola M
Date Issued
July 2013
Journal
Journal of Physical Oceanography
Publisher
American Meteorological Society
Citation
Wang, Jinbo, Michael A. Spall, Glenn R. Flierl, and Paola Malanotte-Rizzoli. “Nonlinear Radiating Instability of a Barotropic Eastern Boundary Current.” J. Phys. Oceanogr. 43, no. 7 (July 2013): 1439–1452. © 2013 American Meteorological Society
Version
Final published version
Abstract
Linear and nonlinear radiating instabilities of an eastern boundary current are studied using a barotropic quasigeostrophic model in an idealized meridional channel. The eastern boundary current is meridionally uniform and produces unstable modes in which long waves are most able to radiate. These long radiating modes are easily suppressed by friction because of their small growth rates. However, the long radiating modes can overcome friction by nonlinear energy input transferred from the more unstable trapped mode and play an important role in the energy budget of the boundary current system. The nonlinearly powered long radiating modes take away part of the perturbation energy from the instability origin to the ocean interior. The radiated instabilities can generate zonal striations in the ocean interior that are comparable to features observed in the ocean. Subharmonic instability is identified to be responsible for the nonlinear resonance between the radiating and trapped modes, but more general nonlinear triad interactions are expected to apply in a highly nonlinear environment.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Woods Hole Oceanographic Institution
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1175/JPO-D-12-0174.1
