Evidence for slow mixing across the pycnocline from an open-ocean tracer-release experiment

  title={Evidence for slow mixing across the pycnocline from an open-ocean tracer-release experiment},
  author={James R. Ledwell and Andrew J. Watson and Cliff S. Law},
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 of the invasion of anthropogenic tracers, such as bomb tritium and 3He (see, for example, refs 1 and 2), have indicated that isopycnal processes dominate diapycnal mixing, and turbulence measurements have suggested that diapycnal mixing is small3,4, but it has not been possible to measure accurately… 
Can We Infer Diapycnal Mixing Rates from the World Ocean Temperature–Salinity Distribution?
AbstractThe turbulent diapycnal mixing in the ocean is currently obtained from microstructure and finestructure measurements, dye experiments, and inverse models. This study presents a new method
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Diapycnal and along isopycnal mixing, estimated from the tracer release experiment, at the North Atlantic oxygen minimum zone
A deliberate Guinea Upwelling Tracer Release Experiment (GUTRE) in 2008 - 2010 was used to study diapycnal mixing and lateral stirring in the thermocline of tropical northeastern Atlantic. The
Spatially heterogeneous diapycnal mixing in the abyssal ocean: A comparison of two parameterizations to observations
[1] The spatial distributions of the diapycnal diffusivity predicted by two abyssal mixing schemes are compared to each other and to observational estimates based on microstructure surveys and
The δ18O of dissolved O2 as a tracer of mixing and respiration in the mesopelagic ocean
The isotopic composition of dissolved oxygen in the mesopelagic ocean is a unique tracer of respiration and transport. New δ18O of O2 data from the tropical South Atlantic oxygen minimum zone are
A Basinwide Estimate of Vertical Mixing in the Upper Pycnocline: Spreading of Bomb Tritium in the North Pacific Ocean
Abstract The vertical diffusivity KV in the upper half-kilometer of the North Pacific subtropical pycnocline is estimated from observations of the spreading rate of anthropogenic tritium. The
Modeling the impact of fronts and mesoscale circulation on the nutrient supply and biogeochemistry of the upper ocean
A new model for three-dimensional mesoscale flow is used to simulate the vertical transport of nutrients into the euphotic zone from deeper waters. We use the model to diagnose the effects of
Comparison of shear measurements and mixing predictions with a direct observation of diapycnal mixing in the Atlantic thermocline
Four sets of velocity and density profiles have been measured with an autonomous profiler during an upper ocean intentional-tracer (SF6) diapycnal diffusivity measurement, the North Atlantic Tracer
Diapycnal diffusivity at the upper boundary of the tropical North Atlantic oxygen minimum zone
A deliberate tracer release experiment in 2008–2010 was used to study diapycnal mixing in the tropical northeastern Atlantic. The tracer (CF3SF5) was injected on the isopycnal surface σΘ = 26.88 kg


The Santa Monica Basin tracer experiment: A study of diapycnal and isopycnal mixing
We have studied cross isopycnal (diapycnal) and lateral mixing and stirring below the sill of Santa Monica Basin by releasing two tracers, sulfur hexafluoride and perfluorodecalin, as close as
Mixing in the Main Thermocline
Abstract A series of profiles of velocity microstructure along 152°E in the western North Pacific Ocean were collected in May–June 1982. Large, averaged turbulent dissipation rates, ϵ, found in the
Baroclinic Flow and Transient-Tracer Fields in the Canary–Cape Verde Basin
Simulated transient-tracer distributions (tritium, 3H3, freons) on the isopycnal horizons σ0=26.5 and 26.8 kg m−3 are presented for the East Atlantic, 10° −40°N. Tracer transport is modeled by
Nitrogen transport by vertically migrating diatom mats in the North Pacific Ocean
PHYTOPLANKTON production in the surface waters of stratified oceans is fed mainly by nitrogen that has been recycled within the euphotic zone1. The nitrogen that is lost from surface waters as
Nitrate flux into the euphotic zone near Bermuda
Throughout most of the year, there exists within the North Atlantic subtropical ocean mixed layer a3He excess which can only be attributed to a flux of tritiugenic3He from below. The upward flux
The Ventilated Thermocline
Abstract A simple theoretical model for the oceanic thermocline and the associated field of current is presented. The model consists of a finite but arbitarily large number of inviscid, homogeneous
Scaling turbulent dissipation in the thermocline
  • M. Gregg
  • Physics, Environmental Science
  • 1989
By comparing observations from six diverse sites in the mid-latitude thermocline, we find that, to within a factor of 2, 〈eIW〉=7×10‐10〈N2/N02〉〈S104/SGM4〉 W kg‐1, where 〈eIW〉 is the average
The Santa Monica Basin tracer experiment: Comparison of release methods and performance of perfluorodecalin and sulfur hexafluoride
We describe the methods used to prepare and inject sulfur hexafluoride (SF6) and perfluorodecalin (PFD) for the Santa Monica Basin tracer experiment. The use of two tracers gave quasi-independent