Estimates and Implications of Surface Eddy Diffusivity in the Southern Ocean Derived from Tracer Transport

Marshall, John; Shuckburgh, Emily; Jones, Helen; Hill, Chris

doi:10.1175/jpo2949.1

Cited by 200 publications

(280 citation statements)

References 42 publications

Supporting

Mentioning

249

Contrasting

Order By: Relevance

“…Estimates from observations (e.g. Ledwell et al, 1998;Bauer et al, 1998;Sundermeyer and Price, 1998;Zhurbas and Oh, 2003;Marshall et al, 2006) and high-resolution ocean models (e.g. Bryan et al, 1999;Eden, 2006;Eden et al, 2007) have revealed pronounced variability of eddy diffusivity in space and time.…”

Section: Neutral and Thickness Diffusivitymentioning

confidence: 99%

The Finite Element Sea Ice-Ocean Model (FESOM) v.1.4: formulation of an ocean general circulation model

et al. 2014

View full text Add to dashboard Cite

Abstract. The Finite Element Sea Ice-Ocean Model (FE-SOM) is the first global ocean general circulation model based on unstructured-mesh methods that has been developed for the purpose of climate research. The advantage of unstructured-mesh models is their flexible multi-resolution modelling functionality. In this study, an overview of the main features of FESOM will be given; based on sensitivity experiments a number of specific parameter choices will be explained; and directions of future developments will be outlined. It is argued that FESOM is sufficiently mature to explore the benefits of multi-resolution climate modelling and that its applications will provide information useful for the advancement of climate modelling on unstructured meshes.

show abstract

Section: Neutral and Thickness Diffusivitymentioning

confidence: 99%

The Finite Element Sea Ice-Ocean Model (FESOM) v.1.4: formulation of an ocean general circulation model

et al. 2014

View full text Add to dashboard Cite

show abstract

“…This suggests that eddy transport is greatest near the mean current itself, as eddy mixing scales with eddy kinetic energy (EKE ;Prandtl 1925;Holloway 1986). However, there is a growing body of evidence suggesting that the mean flow also suppresses mixing (e.g., Bower et al 1985;Nakamura and Ma 1997;Haynes and Shuckburgh 2000a,b;Allen and Nakamura 2001;Marshall et al 2006;Abernathey et al 2010;Ferrari and Nikurashin 2010). Thus assessing cross-jet transport involves finding the balance between the enhancement of mixing by instability and the suppression imposed by the mean.…”

Section: Introductionmentioning

confidence: 99%

Estimating Suppression of Eddy Mixing by Mean Flows

Klocker

Ferrari

LaCasce

2012

Journal of Physical Oceanography

102

View full text Add to dashboard Cite

Particle-and tracer-based estimates of lateral diffusivities are used to estimate the suppression of eddy mixing across strong currents. Particles and tracers are advected using a velocity field derived from sea surface height measurements from the South Pacific, in a region west of Drake Passage. This velocity field has been used in a companion paper to show that both particle-and tracer-based estimates of eddy diffusivities are equivalent, despite recent claims to the contrary. These estimates of eddy diffusivities are here analyzed to show 1) that the degree of suppression of mixing across the strong Antarctic Circumpolar Current is correctly predicted by mixing length theory modified to include eddy propagation along the mean flow and 2) that the suppression can be inferred from particle trajectories by studying the structure of the autocorrelation function of the particle velocities beyond the first zero crossing. These results are then used to discuss how to compute lateral and vertical variations in eddy diffusivities using floats and drifters in the real ocean.

show abstract

“…Here, we apply similar relations to an OGCM that is used to simulate tracer concentration from idealized pulse releases from the British nuclear fuel reprocessing plants at Sellafield and Dounreay. Advanced methods for extracting the equivalent diffusion have been developed and applied to both atmospheric (Haynes and Shuckburgh, 2000) and oceanic flows (Marshall et al, 2006), however, a simpler approach is taken here that is tailored for tracers with a point source release.…”

Section: Introductionmentioning

confidence: 99%

Diagnosing ocean tracer transport from Sellafield and Dounreay by equivalent diffusion and age

et al. 2008

View full text Add to dashboard Cite

A simple approach for estimating the equivalent diffusion for diagnosing tracer transport is proposed. Two different expressions are derived; one is based directly on an analytical solution of the two-dimensional advection-diffusion equation, the other uses the variance of the tracer distribution. To illustrate some features of the equivalent diffusion and possible applications thereof, idealized releases of passive tracers from the nuclear fuel reprocessing plants at Sellafield in the Irish Sea and Dounreay on the northern coast of Scotland have been simulated with a regional isopycnic co-ordinate Ocean General Circulation Model. Both continuous and pulse releases are considered; the former being representative of the actual historical discharges from the reprocessing plants, the latter resembling an accidental scenario. Age tracers are included to calculate the mean time elapsed since the tracers left their source regions. It is found that in the Nordic Seas the age of tracers from Dounreay is approximately 2 years younger than the age from Sellafield. Although tracers from both sources eventually end up along the same transport routes, significant qualitative differences regarding the dispersion properties are found. It is argued that one single parameter, the equivalent horizontal diffusion, which is estimated to be in the range of 20-56 m 2 s −1 from Sellafield and 170-485 m 2 s −1 from Dounreay, determines these differences.

show abstract

Estimates and Implications of Surface Eddy Diffusivity in the Southern Ocean Derived from Tracer Transport

Cited by 200 publications

References 42 publications

The Finite Element Sea Ice-Ocean Model (FESOM) v.1.4: formulation of an ocean general circulation model

The Finite Element Sea Ice-Ocean Model (FESOM) v.1.4: formulation of an ocean general circulation model

Estimating Suppression of Eddy Mixing by Mean Flows

Diagnosing ocean tracer transport from Sellafield and Dounreay by equivalent diffusion and age

Contact Info

Product

Resources

About