Rapid cross-density ocean mixing at mid-depths in the Drake Passage measured by tracer release

  title={Rapid cross-density ocean mixing at mid-depths in the Drake Passage measured by tracer release},
  author={Andrew J. Watson and James R. Ledwell and Marie-Jos{\'e} Messias and Brian A. King and Neill Mackay and Michael P. Meredith and Benjamin J. W. Mills and Alberto Naveira Garabato},
Diapycnal mixing (across density surfaces) is an important process in the global ocean overturning circulation. Mixing in the interior of most of the ocean, however, is thought to have a magnitude just one-tenth of that required to close the global circulation by the downward mixing of less dense waters. Some of this deficit is made up by intense near-bottom mixing occurring in restricted ‘hot-spots’ associated with rough ocean-floor topography, but it is not clear whether the waters at mid… 
Topographic enhancement of vertical turbulent mixing in the Southern Ocean
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Multi-timescale control of Southern Ocean diapycnal mixing over Atlantic tracer budgets
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Diapycnal motion, diffusion, and stretching of tracers in the ocean
Small-scale mixing drives the diabatic upwelling that closes the abyssal ocean overturning circulation. Measurements of in-situ turbulence reveal that mixing is bottom-enhanced over rough topography,
Spatial and seasonal variability of global ocean diapycnal transport inferred from Argo profiles
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Diapycnal mixing in the Southern Ocean diagnosed using the DIMES Tracer and Realistic Velocity Fields
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Transformation of Deep Water Masses Along Lagrangian Upwelling Pathways in the Southern Ocean: SOUTHERN OCEAN UPWELLING TRANSFORMATION
Upwelling of northern deep waters in the Southern Ocean is fundamentally important for the closure of the global meridional overturning circulation and delivers carbon and nutrient-rich deep waters
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Observations of a diapycnal shortcut to adiabatic upwelling of Antarctic Circumpolar Deep Water
In the Southern Ocean, small‐scale turbulence causes diapycnal mixing which influences important water mass transformations, in turn impacting large‐scale ocean transports such as the Meridional
Modification of the deep salinity-maximum in the Southern Ocean by circulation in the Antarctic Circumpolar Current and the Weddell Gyre
The evolution of the deep salinity-maximum associated with the Lower Circumpolar Deep Water (LCDW) is assessed using a set of 37 hydrographic sections collected over a 20-year period in the Southern
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Evidence for enhanced mixing over rough topography in the abyssal ocean
This amount of mixing, probably driven by breaking internal waves that are generated by tidal currents flowing over the rough bathymetry, may be large enough to close the buoyancy budget for the Brazil basin and suggests a mechanism for closing the global overturning circulation.
Seasonal and spatial variations of Southern Ocean diapycnal mixing from Argo profiling floats
in the large-scale ocean circulation and climate 4‐6 . Here we use high-resolution hydrographic profiles from Argo floats in combination with the Iridium communications system to investigate
Diapycnal Mixing in the Antarctic Circumpolar Current
The vertical dispersion of a tracer released on a density surface near 1500-m depth in the Antarctic Circumpolar Current west of Drake Passage indicates that the diapycnal diffusivity, averaged over
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Abstract By convention, the ocean’s large-scale circulation is assumed to be a thermohaline overturning driven by the addition and extraction of buoyancy at the surface and vertical mixing in the
Diagnosing the Southern Ocean Overturning from Tracer Fields
Abstract The strength and structure of the Southern Hemisphere meridional overturning circulation (SMOC) is related to the along-isopycnal and vertical mixing coefficients by analyzing tracer and
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THE distributions of heat, salt and trace substances in the ocean thermocline depend on mixing along and across surfaces of equal density (isopycnal and diapycnal mixing, respectively). Measurements
Global Ocean Meridional Overturning
Abstract A decade-mean global ocean circulation is estimated using inverse techniques, incorporating air–sea fluxes of heat and freshwater, recent hydrographic sections, and direct current
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Ocean microstructure data show that turbulent mixing in the deep Brazil Basin of the South Atlantic Ocean is weak at all depths above smooth abyssal plains and the South American Continental Rise, which implies that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry.