Oceanic isopycnal slope spectra. Part II: Turbulence

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Non
Statut de publication : Publié
Année de publication : 2007
Auteurs (2) : KLYMAK Jody,m MOUM James
Revue scientifique : Journal of Physical Oceanography
Volume : 37
Fascicule : 5
Pages : 1232-1245
DOI : 10.1175/JPO3074.1
URL : -
Abstract : Isopycnal slope spectra were computed from thermistor data obtained using a microstructure platform towed through turbulence generated by internal tidal motions near the Hawaiian Ridge. The spectra were compared with turbulence dissipation rates epsilon that are estimated using shear probes. The turbulence subrange of isopycnal slope spectra extends to surprisingly large horizontal wavelengths (> 100 m). A four-order-of-magnitude range in turbulence dissipation rates at this site reveals that isopycnal slope spectra alpha epsilon(2/3)k(x)(1/3). The turbulence spectral subrange (k(x) > 0.4 cpm) responds to the dissipation rate as predicted by the Batchelor model spectrum, both in amplitude and towed vertical coherence. Scales between 100 and 1000 m are modeled by a linear combination of internal waves and turbulence while at larger scales internal waves dominate. The broad bandwidth of the turbulence subrange means that a fit of spectral amplitude to the Batchelor model yields reasonable estimates of epsilon, even when applied at scales of tens of meters that in vertical profiles would be obscured by other fine structure.
Mots-clés : DISSIPATION MEASUREMENTS; ENERGY; HAWAIIAN RIDGE; INTERNAL WAVE FIELD; MICROSTRUCTURE; OVERTURNS; SARGASSO SEA; SEASONAL THERMOCLINE; STRATIFIED FLUID; TEMPERATURE
Commentaire : Times Cited in Web of Science Core Collection: 45
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Citation :
Klymak JM, Moum J (2007) Oceanic isopycnal slope spectra. Part II: Turbulence. J Phys Oceanogr 37: 1232-1245 | doi: 10.1175/JPO3074.1