A Greenland Sea perspective on the dynamics of postconvective eddies

Oliver, K. I. C., Eldevik, T., Stevens, D. P. ORCID: https://orcid.org/0000-0002-7283-4405 and Watson, A. J. (2008) A Greenland Sea perspective on the dynamics of postconvective eddies. Journal of Physical Oceanography, 38 (12). pp. 2755-2771.

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Abstract

Open ocean deep postconvection contributes to the formation of the dense waters that fill the global deep ocean. The dynamics of postconvective vortices are key to understanding the role of convection in ocean circulation. Submesoscale coherent vortices (SCVs) observed in convective regions are likely to be the anticyclonic components of hetons. Hetons are dipoles, consisting of a surface cyclone and a weakly stratified subsurface anticyclone, that can be formed by convection. Here, key postconvective processes are investigated using numerical experiments of increasing sophistication with two primary goals: 1) to understand how the ambient hydrography and topography influence the propagation of hetons and 2) to provide a theoretical context for recent observations of SCVs in the Greenland Sea. It is found that the alignment of hetons is controlled by ambient horizontal density gradients and that hetons self-propagate into lighter waters as a result. This provides a mechanism for transporting convected water out of a cyclonic gyre, but the propagation is arrested if the heton meets large-amplitude topography. Upon interaction with topography, hetons usually separate, and the surface cyclone returns toward denser water. The anticyclone usually remains close to topography and may become trapped for several hundred days. These findings may explain the observed accumulation and longevity of SCVs at the Greenland Fracture Zone, on the rim of the Greenland Sea gyre. The separation and sorting of cyclones from anticyclones have likely implications for the density and vorticity budgets of convective regions.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Environmental Sciences Faculty of Science > School of Mathematics (former - to 2024)
UEA Research Groups:	Faculty of Science > Research Groups > Fluid and Solid Mechanics (former - to 2024) Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Fluids & Structures Faculty of Science > Research Groups > Numerical Simulation, Statistics & Data Science
Depositing User:	Rosie Cullington
Date Deposited:	25 Feb 2011 15:00
Last Modified:	07 Nov 2024 12:33
URI:	https://ueaeprints.uea.ac.uk/id/eprint/24675
DOI:	10.1175/2008JPO3844.1

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