Some observations of thermo-haline stratification in the deep ocean

Howe, M.R.; Tait, R.I.

doi:10.1016/0011-7471(68)90005-3

Cited by 66 publications

(37 citation statements)

References 3 publications

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“…for flux computation and for tracing staircase extents, other methods might be more useful. These could be based on qualitative signatures that have been used informally for decades, based on finescale signatures on and ¡ profiles and in ¡ diagrams (Tait and Howe, 1968;Neal et al, 1969;Fedorov, 1970). Steppy profiles are often taken as evidence of thermohaline staircases of DDC origin, but some provisos are required.…”

Section: Detection Methodsmentioning

confidence: 99%

The diffusive regime of double-diffusive convection

Kelley

Fernando

Gargett

et al. 2003

Progress in Oceanography

171

187

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The diffusive regime of double-diffusive convection is reviewed, with a particular focus on issues that are holding up the development of large-scale parameterizations. Some of these issues, such as interfacial transports and layer-interface interactions, may be studied in isolation. Laboratory work should help with these. However, we must also face more difficult matters that relate to oceanic phenomena that are not easily represented in the laboratory. These lie beneath some fundamental questions about how double-diffusive structures are formed in the ocean, and how they evolve in the competitive ocean environment.

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Section: Detection Methodsmentioning

confidence: 99%

The diffusive regime of double-diffusive convection

Kelley

Fernando

Gargett

et al. 2003

Progress in Oceanography

171

187

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“…Sheets and layers have been observed in the ocean where the stability ratio ( OtTz/Sz ) approaches 1.0 (Tait andHowe, 1968, Lambert andSturges, 1977).…”

Section: 4mentioning

confidence: 99%

Wintertime convection and frontal interleaving in the Southern Ocean

Toole¹

1980

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The Southern Ocean as defined here is the body of water between the Antarctic Continent and the Antarctic Polar Front, (APF).This ocean is considered important in the global thermodynamic balance of the ocean-atmosphere system because large planetary heat losses are believed to occur at high latitudes.The ocean and atmosphere must transport heat poleward to balance these losses.In the Southern Hemisphere, the oceanic contribution to this flux involves a southward transport of heat across the APF into the Southern Ocean where it is given up to the atmosphere through air-sea interactions.In Part I, the air-sea interactions and structure of the' near surface waters of the Southern Ocean are investigated with a three dimensional time dependent numerical model.The surface waters in this region in summer are characterized by a relatively warm surface mixed layer with low salinity.Below this layer, a cold temperature extremum is usually observed in vertical profiles which is believed to be the remnant of a deep surface mixed layer produced in winter.The characteristics of this layer, the surface mixed layer and the observed distribution of wintertime sea ice are reproduced well by this model.Unlike some other sea-ice models the air-sea heat exchange is a free variable.Model estimates of the annual heat loss by the Southern Ocean exhibit the observed meridional variation of heat gained by the ocean along the APF with heat lost further south.The model's area average heat loss is much smaller than that estimated with direct observations. While several model parameterizations were made which could be in error, the model results suggest that the Southern Ocean does give up vast amounts of heat to the atmosphere away from the continental margins.The model results and direct calculations of air-sea exchanges suggest a southward heat flux must occur across the APF.The lateral water mass transition across the front is not discontinuous but occurs over a finite sized zone of fluid which is dominated by intrusive finestructure.The characteristics and dynamics of these features are investigated in Part II to try and assess their importance in the meridional heat budget. Abstract (Contd.)Observations made on two cruises to the APF are presented and the space-time scales of the features and thermohaline characteristics are discussed. It is suggested that double diffusive processes dominated by salt fingering are active within the intrusions.An extension of Stern's (1967) model of the stability of a thermohaline front to intrusive finestructure driven by saltfingering where-small scale viscous processes are included, is presented to explain why intrusions are observed in frontal zones.The model successfully predicts vertical scales of intrusions observed in the ocean and the observed dependence of the intrusions' slopes across density surfaces on the vertical scale.Since the fastest growing intrusion is not strongly determined by the model, though, it is likely that finite amplitude effects determine the dominant scale of int...

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“…These features were collectively called "microstructure. " Cooper and Stommel (1968), Stommel and Federov (1968), and Tait and Howe (1968) provided some of the first deep ocean microstructure observations.…”

Section: Spectra Of Ucor Vcormentioning

confidence: 99%

Measurements and models of fine structure, internal gravity waves, and wave breaking in the deep Ocean

Eriksen¹

1978

J. Geophys. Res.

110

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Measurements of horizontal and vertical current by propeller cluster current meters and temperature by thermistors mounted on a rigid array 8 m high and 20 m long moored in the oceanic main thermocline near Bermuda are interpreted in terms of thermocline-trapped internal wave modes in the presence of temperature and density fine-structure.Two turning-point uniformly valid asymptotic solutions to the internal wave equation are developed to describe the wave functions. Mode decay beyond the turning point in depth or frequency produces a sharp cutoff in vertical current spectra above the local buoyancy frequency N(z). An internal wave wavenumber-frequency spectral model E(a,w) = E()/No)-2(a/ao)-2 describes vertical current spectra and potential energy to horizontal kinetic energy ratios. The red wavenumber shape suppresses peaks in both these quantities at frequencies near N(z).The data are consistent with time-averaged horizontal isotropy of the wave field. A dip in the vertical current spectra at 0.5 cph not predicted by the model appears related to the bottom slope.Temperature fine-structure is modeled as a passive vertical field advected by internal waves. Quasi-permanent fine-scale features of the stratification and vertically small-scale internal waves are indistinguishable in this study. The model of McKean (1974) is generalized to include fine-structure fields specified by their vertical wavenumber spectra as well as different Poisson-distributed layer models. Together with the trapped internal wave model, moored temperature spectra, temperature vertical difference spectra, and coherence over vertical separations are described using a fine-structure vertical wavenumber spectrum PT(k) = ATk-5 / 2 which agrees with other spectra made using vertical profiling instruments in the range 0.1 to 1.0 cpm.Horizontal current fine-structure is also modeled as a passive field advected vertically by long internal waves. The model describes moored horizontal current spectra (least successfully at frequencies near N(z)) and finite-difference vertical shear spectra. 3Contours of temperature in depth versus time indicate possible mixing events. These events appear concurrently with high shear and Richardson numbers 0.25 < R < 1.0. Over 7 m a cutoff in R i at 0.25 is observed, indicating saturation of the internal wave spectrum. Spectra of finite-difference approximations to shear and buoyancy frequency are dominated by fine-structure contributions over nearly the whole internal wave range, suggesting that breaking is enhanced by fine-structure. Breaking appears equally likely at all frequencies in the internal wave range.

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Some observations of thermo-haline stratification in the deep ocean

Cited by 66 publications

References 3 publications

The diffusive regime of double-diffusive convection

The diffusive regime of double-diffusive convection

Wintertime convection and frontal interleaving in the Southern Ocean

Measurements and models of fine structure, internal gravity waves, and wave breaking in the deep Ocean

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