Oceanic thermohaline intrusions: observations

Ruddick, Barry; Richards, Kelvin J

doi:10.1016/s0079-6611(03)00028-4

Cited by 74 publications

(67 citation statements)

References 115 publications

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“…However, since the vertical flux of salt dominates over heat, the resultant lateral fluxes actually show a greater transport of heat than salt, since the temperature field is less "short-circuited" by the small-scale double diffusion (Ruddick and Richards, 2003).…”

Section: Double Diffusive Effectsmentioning

confidence: 99%

The East Greenland boundary current system south of Denmark Strait

Brearley

Pickart

Valdimarsson

et al. 2012

Deep Sea Research Part I: Oceanographic Research Papers

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Four repeat sections across the East Greenland shelf and slope south of Denmark Strait are analysed to investigate the components of the boundary current system. The sections were occupied in summer 2001, 2003, 2004, and 2007, and included use of a vessel-mounted acoustic Doppler current profiler, enabling the computation of absolute geostrophic velocities. The components of the boundary current are the East Greenland/Irminger Current (EGIC) in the upper layer, the Deep Western Boundary Current (DWBC) at the base of the continental slope, and the East Greenland spill jet which resides inshore and beneath the EGIC. Special emphasis is placed on the spill jet, a recently discovered feature about which relatively little is known. The spill jet was observed in each occupation, transporting 5.0 ± 2.2 Sv equatorward in the mean, which is similar to the DWBC at this latitude (4.9 ± 1.4 Sv). The spill jet displayed considerable variability between sections, which appears to be linked to the geographical location of the upper-layer hydrographic front associated with the EGIC. When the front is located near the shelfbreak, the spill jet is confined to the outer shelf/upper slope and its transport is smaller. During these times there is less mixing and the water advected by the jet is generally lighter than that transported by the DWBC. In contrast, when the front is located seaward of the shelfbreak, the spill jet extends farther down the continental slope and its volume flux is larger. At these times, there is stronger mixing and the spill jet can transport water as dense as the Denmark Strait Overflow Water. A vorticity analysis indicates that the jet is susceptible to a variety of instability processes including baroclinic, barotropic, and symmetric instability. In addition, it is subject to double diffusive mixing that may influence its downstream evolution. It appears that the 2 spill jet is a permanent feature of the summertime circulation in this region and contributes significantly to the intermediate, and at times deep, limb of the Atlantic Meridional Overturning Circulation.

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Section: Double Diffusive Effectsmentioning

confidence: 99%

The East Greenland boundary current system south of Denmark Strait

Brearley

Pickart

Valdimarsson

et al. 2012

Deep Sea Research Part I: Oceanographic Research Papers

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“…Indeed, Johnson and Kearney (2009) find that fingers have attenuated the signals of climate change in the thermocline. Discussions of various aspects of double-diffusion have been provided by a collection of reviews introduced by Ruddick and Gargett (2003), including work on salt fingers (Kunze, 2003;Schmitt, 2003;Yoshida and Nagashima, 2003a) diffusive-convection (Kelley et al., 2003) and doublediffusive intrusions (Ruddick and Kerr, 2003;Ruddick and Richards, 2003;Yoshida and Nagashima, 2003b). Stern himself continued to make significant contributions to double-diffusive theory throughout his career (Stern et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Thermohaline convection at density ratios below one: A new regime for salt fingers

Schmitt¹

2011

j mar res

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New experimental results on haline convection show a surprising preference for narrow fingers over large-scale convection when even a small stabilizing temperature gradient is present (Hage and Tilgner, 2010). This regime has heat/salt density ratios below one, a parameter range that has not been explored in traditional salt finger theory. Here the properties of the exact (long finger) solutions of Schmitt (1979Schmitt ( , 1983) are explored at low density ratios. It is found that narrow finger solutions are indeed obtained and remain the fastest growing in some circumstances, though the selective advantage of the "Stern scale" can disappear as the density ratio decreases. The variation of solutions with Prandtl number and the relation to the Stern (1975) approximate solution are examined and discussed.

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“…In the convectively unstable regions, a pre-determined convective diffusivity turns on and off without accounting for the degree of static instability. For a more comprehensive overview of the theory, laboratory studies, and observations of thermohaline interleaving, the reader is referred to Ruddick and Kerr (2003), Ruddick (2003), and Ruddick and Richards (2003).…”

Section: Introductionmentioning

confidence: 99%

Shear and Convective Turbulence in a Model of Thermohaline Intrusions

Mueller

Smyth

Ruddick

2007

Journal of Physical Oceanography

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Thermohaline interleaving is an important mechanism for laterally fluxing salt, heat, and nutrients between water masses. Interleaving is driven by a release of potential energy resulting from the vastly differing diffusivities of heat and salt in seawater. The flows are composed of stacked intrusions that flux more buoyant and less buoyant water in opposite directions. In this paper, we investigate the role of shear instability caused by this juxtaposed motion. The model described in Walsh and Ruddick (1998) is modified to include effects of shear induced turbulence and an improved convective mixing parameterization. Shear and convective mixing play a similar and significant role in interleaving dynamics. In the absence of either instability, cross-front fluxes are increased by approximately 30%. While in situ observations of horizontal diffusivity due to interleaving are not yet precise enough to calibrate the parameterizations independently, parameter values based on independent lab and numerical studies lead to diffusivity predictions that are within error of the observations.

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Oceanic thermohaline intrusions: observations

Cited by 74 publications

References 115 publications

The East Greenland boundary current system south of Denmark Strait

The East Greenland boundary current system south of Denmark Strait

Thermohaline convection at density ratios below one: A new regime for salt fingers

Shear and Convective Turbulence in a Model of Thermohaline Intrusions

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