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Global Observations Of Horizontal Mixing From Argo Float And Surface Drifter Trajectories

Title: Global Observations Of Horizontal Mixing From Argo Float And Surface Drifter Trajectories.
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Name(s): Roach, Christopher J., author
Balwada, Dhruv, author
Speer, Kevin, author
Type of Resource: text
Genre: Journal Article
Text
Journal Article
Date Issued: 2018-07-01
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Mixing by mesoscale eddies in the ocean plays a major role in setting the distribution of oceanic tracers, with important implications for physical and biochemical systems at local to global scales. Roach et al. (2016; https://doi.org/10.1002/2015JC011440) demonstrated that a two-particle analysis of Argo trajectories produces robust estimates of horizontal mixing in the Southern Ocean. Here we extend this analysis to produce global 1 degrees x1 degrees maps of eddy diffusivity at the nominal Argo parking depth of 1,000 m. We also applied this methodology to estimate surface eddy diffusivities from Global Drifter Program (GDP) surface drifters. The global mean eddy diffusivity was 543 +/- 155 m(2)/s at 1,000m and 2637 +/- 311 m(2)/s at the surface, with elevated diffusivities in regions of enhanced eddy kinetic energy, such as western boundary currents and along the Antarctic Circumpolar Current. The eddy kinetic energy at the equator is high at both the surface and depth, but the eddy diffusivity is only enhanced near the surface. At depth the eddy diffusivity is strongly suppressed due to the presence of mean flow. We used our observational estimates to test the validity of an eddy diffusivity parameterization that accounts for mixing suppression in the presence of zonal mean flows. Our results indicated that this parameterization generally agrees with the directly observed eddy diffusivities in the midlatitude and high-latitude oceans.
Identifier: FSU_libsubv1_wos_000441888200008 (IID), 10.1029/2018JC013750 (DOI)
Keywords: variability, parameterization, north-atlantic, pacific-ocean, southern-ocean, overturning circulation, Argo floats, drifters, isopycnal mixing, Lagrangian methods, lateral eddy diffusivity, ocean circulation models, relative dispersion, tracer
Publication Note: The publisher’s version of record is available at https://doi.org/10.1029/2018JC013750
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000441888200008
Owner Institution: FSU
Is Part Of: Journal of Geophysical Research-Oceans.
2169-9275
Issue: iss. 7, vol. 123

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Roach, C. J., Balwada, D., & Speer, K. (2018). Global Observations Of Horizontal Mixing From Argo Float And Surface Drifter Trajectories. Journal Of Geophysical Research-Oceans. Retrieved from http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000441888200008