Instability-Driven Benthic Storms Below the Separated Gulf Stream and the North Atlantic Current in a High-Resolution Ocean Model.

Schubert, René, Biastoch, Arne , Cronin, Meghan F. and Greatbatch, Richard John (2018) Instability-Driven Benthic Storms Below the Separated Gulf Stream and the North Atlantic Current in a High-Resolution Ocean Model. Open Access Journal of Physical Oceanography, 48 . pp. 2283-2303. DOI 10.1175/JPO-D-17-0261.1.

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Abstract

Benthic storms are important for both the energy budget of the ocean and for sediment resuspension and transport. Using 30 years of output from a high-resolution model of the North Atlantic, it is found that most of the benthic storms in the model occur near the western boundary in association with the Gulf Stream and the North Atlantic Current, in regions that are generally co-located with the peak near-bottom eddy kinetic energy. A common feature are meander troughs in the near-surface jets that are accompanied by deep low pressure anomalies spinning up deep cyclones with near-bottom velocities of up to more than 0.5 m/s. A case study of one of these events shows the importance of both baroclinic and barotropic instability of the jet, with energy being extracted from the jet in the upstream part of the meander trough and partly returned to the jet in the downstream part of the meander trough. This motivates examining the 30-year time mean of the energy transfer from the (annual mean) background flow into the eddy kinetic energy. This quantity is shown to be co-located well with the region in which benthic storms and large increases in deep cyclonic relative vorticity occur most frequently, suggesting an important role for mixed barotropic-baroclinic instability driven cyclogenesis in generating benthic storms throughout the model simulation. Regions of largest energy transfer and most frequent benthic storms are found to be the Gulf Stream west of the New England Seamounts and the North Atlantic Current near Flemish Cap.

Document Type: Article
Additional Information: This is a preliminary PDF of the author-produced manuscript that has been peer-reviewed and accepted for publication. Since it is being posted so soon after acceptance, it has not yet been copyedited, formatted, or processed by AMS Publications. This preliminary version of the manuscript may be downloaded, distributed, and cited, but please be aware that there will be visual differences and possibly some content differences between this version and the final published version.
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1175/JPO-D-17-0261.1
ISSN: 0022-3670
Projects: RACE, DRAKKAR
Expeditions/Models/Experiments:
Date Deposited: 13 Aug 2018 08:43
Last Modified: 06 Feb 2020 09:01
URI: http://oceanrep.geomar.de/id/eprint/43975

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