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| Titel |
Vertical mixing and coherent anticyclones in the ocean: the role of stratification |
| VerfasserIn |
I. Koszalka, L. Ceballos, A. Bracco |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 17, no. 1 ; Nr. 17, no. 1 (2010-01-22), S.37-47 |
| Datensatznummer |
250013635
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| Publikation (Nr.) |
 copernicus.org/npg-17-37-2010.pdf |
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| Zusammenfassung |
The role played by wind-forced anticyclones in the vertical transport and
mixing at the ocean mesoscale is investigated with a primitive-equation
numerical model in an idealized configuration. The focus of this work is to
determine how the stratification impacts such transport.
The flows, forced only at the surface by an idealized wind forcing, are
predominantly horizontal and, on average, quasigeostrophic. Inside vortex
cores and intense filaments, however, the dynamics is strongly ageostrophic.
Mesoscale anticyclones appear as "islands" of increased penetration of wind
energy into the ocean interior and they represent the maxima of available
potential energy. The amount of available potential energy is directly
correlated with the degree of stratification.
The wind energy injected at the surface is transferred at depth through the
generation and subsequent straining effect of Vortex Rossby Waves (VRWs), and
through near-inertial internal oscillations trapped inside anticyclonic
vortices. Both these mechanisms are affected by stratification. Stronger
transfer but larger confinement close to the surface is found when the
stratification is stronger. For weaker stratification, vertical mixing close
to the surface is less intense but below about 150 m attains substantially
higher values due to an increased contribution of both VRWs, whose time scale
is on the order of few days, and of near-inertial motions, with a time scale
of few hours. |
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