Observational Inferences of Lateral Eddy Diffusivity in the Halocline of the Beaufort Gyre
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observational-inferences-lateral.pdf
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Author(s)
Cole, Sylvia T.
Timmermans, Mary-Louise
Meneghello, Gianluca
Marshall, John C
Date Issued
November 2017
Journal
Geophysical Research Letters
Publisher
American Geophysical Union (AGU)
Citation
Meneghello, Gianluca, et al. “Observational Inferences of Lateral Eddy Diffusivity in the Halocline of the Beaufort Gyre.” Geophysical Research Letters, vol. 44, no. 24, Dec. 2017, pp. 12,331-12,338.
Version
Original manuscript
Abstract
Using Ekman pumping rates mediated by sea ice in the Arctic Ocean's Beaufort Gyre (BG), the magnitude of lateral eddy diffusivities required to balance downward pumping is inferred. In this limit—that of vanishing residual-mean circulation—eddy-induced upwelling exactly balances downward pumping. The implied eddy diffusivity varies spatially and decays with depth, with values of 50–400 m[superscript 2]/s. Eddy diffusivity estimated using mixing length theory applied to BG mooring data exhibits a similar decay with depth and range of values from 100 m[superscript 2]/s to more than 600 m[superscript 2]/s. We conclude that eddy diffusivities in the BG are likely large enough to balance downward Ekman pumping, arresting the deepening of the gyre and suggesting that eddies play a zero-order role in buoyancy and freshwater budgets of the BG.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1002/2017GL075126
