On quartet interactions in the California Current system
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Authors
Ivanov, L.M.
Collins, C.A.
Margolina, T.M.
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Date of Issue
2014
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Abstract
Sea surface height (SSH) altimetry observations
for 1992 to 2009 off California are used to show that observed
quasi-zonal jets were likely driven by near-resonance
interactions between different scales of the flow. Quartet
(modulational) instability dominated and caused non-local
transfer of energy from waves and eddies to biannual oscillations
and quasi-zonal jets. Two types of quartets were
identified: those composed of scales corresponding to (a)
quasi-zonal jets, annual and semiannual Rossby waves and
mesoscale eddies, and (b) biannual oscillations, semiannual
Rossby waves and mesoscale eddies. The spectral centroid
regularly shifted into the domain of low-order modes. However,
the spectrum of SSHs does not demonstrate a power behavior.
This says that the classical inverse cascade is absent.
For a case with bottom friction, quartet instability required
the existence of a certain level of dissipativity in the flow.
Type
Article
Description
The article of record as published may be located at http://dx.doi.org/10.5194/npg-21-887-2014
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Support for LI (CC) was provided by NSF grant OCE-0827527 (OCE-0827160).
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Citation
Nonlin. Processes Geophys., 21, 887–900, 2014
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.