Ocean circulation kinetic energy: Reservoirs, sources, and sinks. (English) Zbl 1159.76050

Davis, Stephen H. (ed.) et al., Annual review of fluid mechanics. Vol. 41. Palo Alto, CA: Annual Reviews (ISBN 978-0-8243-0741-7/hbk). Annual Review of Fluid Mechanics 41, 253-282 (2009).
Summary: The ocean circulation is a cause and consequence of fluid scale interactions ranging from millimeters to more than 10,000 km. Although the wind field produces a large energy input to the ocean, all but approximately 10% appears to be dissipated within about 100 m of the sea surface, rendering observations of the energy divergence necessary to maintain the full water-column flow difficult. Attention thus shifts to the physically different kinetic energy (KE) reservoirs of the circulation and their maintenance, dissipation, and possible influence on the very small scales representing irreversible molecular mixing. Oceanic KE is dominated by the geostrophic eddy field, and depending on the vertical structure (barotropic versus low-mode baroclinic), direct and inverse energy cascades are possible. The pathways toward dissipation of the dominant geostrophic eddy KE depend crucially on the direction of the cascade but are difficult to quantify because of serious observational difficulties for wavelengths shorter than approximately 100-200 km. At high frequencies, KE is dominated by internal waves with near-inertial frequencies (frequencies near the local Coriolis parameter), whose shears appear to be a major source of wave breaking and mixing in the ocean interior.
For the entire collection see [Zbl 1155.76006].


76U05 General theory of rotating fluids
86A05 Hydrology, hydrography, oceanography
76-02 Research exposition (monographs, survey articles) pertaining to fluid mechanics
86-02 Research exposition (monographs, survey articles) pertaining to geophysics


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