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Abstract Temperature and salinity measurements of a warm‐core eddy at the northern flank of the Ross Gyre are analyzed for dominant mixing mechanisms. The eddy is centered at the depths of the Circumpolar Deep Water and carries heat towards the gyre. Vertical and horizontal heat fluxes out of the eddy associated with internal wave turbulent mixing and thermohaline intrusions are estimated. Upward internal wave turbulent heat flux isW, whereas, the lateral intrusive heat flux is of the order ofW. The horizontal flux due to intrusions is suggested to be the dominant mechanism for eddy decay and yields an eddy lifetime of about 6 months. The thermohaline intrusion‐eddy suppression mechanism is proposed and shown to be effective in suppressing the eddy field at the northern flank of the Ross Gyre. This effect has important implications for setting the basin‐wide heat budget and regulating sea‐ice cover.
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Dynamical controls on the longevity of a non-linear vortex : The case of the Lofoten Basin Eddy
Abstract The Lofoten Basin is the largest oceanic reservoir of heat in the Nordic Seas, and the site of important heat fluxes to the atmosphere. An intense permanent anticyclone in the basin impacts the regional hydrography, energetics, and ecosystem. Repeated sampling of this Lofoten Basin Eddy from dedicated cruises, autonomous profiling gliders, and acoustically-tracked subsurface floats enables the documentation of its dynamics and energetics over the course of 15 months. The eddy core, in nearly solid-body rotation, exhibits an unusually low vertical vorticity close to the local inertial frequency and important strain rates at the periphery. Subsurface floats as deep as 800 m are trapped within the core for their entire deployment duration (up to 15 months). The potential vorticity is reduced in the core by two orders of magnitude relative to the surroundings, creating a barrier. In the winter, this barrier weakens and lateral exchanges and heat flux between the eddy and the surroundings increase, apparently the result of dynamical instabilities and a possible eddy merger. Based on a simple energy budget, the dissipation timescale for the eddy energy is three years, during which wintertime convection seasonally modulates potential and kinetic energy.
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- Award ID(s):
- 1658564
- PAR ID:
- 10323198
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 9
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s41598-019-49599-8
