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Jörn Callies and Raffaele Ferrari

flows, mixed layer turbulence, near-inertial oscillations, and internal tides. Ferrari and Rudnick (2000) showed that density fronts are weak in the region. We further find that the in situ vertical shear is much greater than the geostrophic shear in both the mixed layer and the thermocline, which contradicts the interpretation in terms of frontal circulations, because in frontal flows, most of the shear is in the along-front component and thus in geostrophic balance. Ekman flows and mixed layer

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Catherine A. Vreugdenhil, Andrew McC. Hogg, Ross W. Griffiths, and Graham O. Hughes

idealized model with differing prescribed diffusivities in a near-surface (thermocline) layer and the deep interior, Scott and Marotzke (2002) concluded that the MOC heat and mass transport were determined mainly by mixing through the thermocline, whereas abyssal mixing did not substantially influence the flow. Saenko and Merryfield (2005) conducted an extensive parameter study into abyssal diffusivity in ocean models and found that while abyssal diffusivity influenced the abyssal circulation and

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Ryan Abernathey and Paola Cessi

current with and without a topographic ridge, with the goal of understanding how zonal asymmetry affects the baroclinic equilibration process. In our simplified experiments, in which the interior of the ocean is quasi adiabatic, the thermocline depth is determined by the competition between poleward cross-frontal heat transport by the geostrophic eddies and the equatorward heat transport by the Ekman circulation. We find that, with localized topography, the eddy field accomplishes the same cross

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Roy Barkan, Kraig B. Winters, and Stefan G. Llewellyn Smith

from classical theory ( Hoskins and Bretherton 1972 ), ageostrophic circulation with downwelling on the cold side of the front and upwelling on the warm side is observed. The correlation between elevated dissipation and downwelling is found all through the thermocline region. The largest values of dissipation, however, are confined to the surface layer (dashed line), as expected from Fig. 16 . Fig. 18. A local region (rectangular box in Fig. 12 ) showing a typical submesoscale frontogenesis in

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Jonathan Gula, M. Jeroen Molemaker, and James C. McWilliams

) , which shows much stronger secondary circulation and intensification rate for cold filaments compared to warm ones. The cause is a horizontal deformation flow that acts on an isolated, favorably aligned filament, causing rapid narrowing and a two-celled secondary circulation with even stronger surface convergence and downwelling at its center than in frontogenesis for a monotonic density gradient (i.e., a conventional front). The Gulf Stream is full of fronts, filaments, and eddies at meso- and

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Xia Liu, Mu Mu, and Qiang Wang

, 2003 : Conditional nonlinear optimal perturbation and its applications . Nonlinear Processes Geophys. , 10 , 493 – 501 , . 10.5194/npg-10-493-2003 Mu , M. , L. Sun , and H. A. Dijkstra , 2004 : The sensitivity and stability of the ocean’s thermocline circulation to finite amplitude freshwater perturbations . J. Phys. Oceanogr. , 34 , 2305 – 2315 ,<2305:TSASOT>2.0.CO;2 . 10

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Takeyoshi Nagai, Amit Tandon, Eric Kunze, and Amala Mahadevan

1. Introduction Most of the power into the ocean’s general circulation arises from stress exerted by the wind at the surface ( Fofonoff 1981 ; Oort et al. 1994 ; Wunsch 1998 ). Because of the ocean’s boundaries, wind patterns, density distribution, and Earth’s rotation, this energy organizes into 100–1000-km gyres and currents and fields of 10–100-km mesoscale eddies. This large-scale quasigeostrophic dynamics arrests transfer of energy to smaller scales where it could be dissipated, instead

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Peter E. Hamlington, Luke P. Van Roekel, Baylor Fox-Kemper, Keith Julien, and Gregory P. Chini

and dynamics ( Spall 1997 ; Haine and Marshall 1998 ; Ferrari and Rudnick 2000 ; Thomas 2005 ; Mahadevan and Tandon 2006 ; Capet et al. 2008b ; Klein and Lapeyre 2009 ). These eddies are typically 1–10 km in horizontal dimension and span the mixed layer depth, which is O (100 m). They may penetrate into the thermocline below and they are typified by their large Rossby numbers, which gives them substantially larger vertical velocities than is typical of larger mesoscale eddies. The potential

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Navid C. Constantinou

baroclinic processes and on the existence channel walls. In the following detailed models of Nadeau and Straub (2009 , 2012 ), Nadeau et al. (2013) , and Nadeau and Ferrari (2015) , the arguments for explaining eddy saturation were barotropic in heart. Specifically, Nadeau and Ferrari (2015) argued that the circulation can be decomposed to a circumpolar mode and a gyre mode (with the latter not contributing to the total transport). Nadeau and Ferrari (2015) showed that the wind stress curl spins

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R. M. Holmes and L. N. Thomas

findings of Qiao and Weisberg (1995) and Inoue et al. (2012) . North of the equator, TIVs centered around 4°N are characterized by an anticyclonic circulation with vorticity close to − f ( f is the Coriolis parameter) that induces variations in zonal velocity and stratification ( Holmes et al. 2014 ; Fig. 2 ). These features and the spatial structure of the TIWs and TIVs are consistent with the observations of Qiao and Weisberg (1995) and Kennan and Flament (2000) . Fig . 1. Daily averaged (a

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