The University of Southampton
University of Southampton Institutional Repository

Remote wind-driven overturning in the absence of the Drake Passage Effect

Remote wind-driven overturning in the absence of the Drake Passage Effect
Remote wind-driven overturning in the absence of the Drake Passage Effect
Zonal wind stress over the Southern Ocean may be responsible for a significant fraction of the meridional overturning associated with North Atlantic Deep Water. Numerical experiments by Tsujino and Suginohara imply that the zonal periodicity of the Southern Ocean is not necessary for midlatitude westerly winds to drive strong remote meridional overturning. Here, idealized numerical experiments examine the importance of zonal periodicity and other factors in setting the sensitivity of this overturning to the wind stress. These experiments support the conclusion that the wind can drive remote overturning in the absence of zonal periodicity. However, making the subpolar ocean zonally periodic roughly doubles the strength of the overturning induced by the wind there. Tsujino and Suginohara's experiments are especially sensitive to wind stress because their basin has a relatively small meridional range, which increases the Ekman transport associated with the wind stress. Depending on the stratification in the wind-forcing region, the heating associated with the westerly winds can occur almost exclusively near the surface or deeper in the thermocline as well. Subsurface cooling in the wind-forcing region reduces the remote effects and can occur through both vertical or horizontal diffusion. A scale analysis of the heat budget suggests that sufficiently strong subpolar westerlies produce remote overturning because there is no way for local cooling to balance wind-induced surface heating. Tsujino and Suginohara suggested that wind increases the overturning by enhancing the mixing-driven thermohaline circulation. However, an increase in thermohaline circulation is associated with increased conversion of turbulent kinetic energy to potential energy. This increase in the energy conversion is absent in the wind-driven case, indicating an important qualitative difference between mixing-driven thermohaline overturning and remote wind-driven overturning.
0022-3670
1036-1049
Klinger, Barry A.
0be849df-8abd-463c-a560-7715cb9f7475
Drijfhout, Sybren
a5c76079-179b-490c-93fe-fc0391aacf13
Marotzke, Jochem
b4b295a3-5568-4f63-94b6-6fa92ab27cf3
Scott, Jeffery R.
0a5b123f-280a-443e-b026-7a010bbe33b5
Klinger, Barry A.
0be849df-8abd-463c-a560-7715cb9f7475
Drijfhout, Sybren
a5c76079-179b-490c-93fe-fc0391aacf13
Marotzke, Jochem
b4b295a3-5568-4f63-94b6-6fa92ab27cf3
Scott, Jeffery R.
0a5b123f-280a-443e-b026-7a010bbe33b5

Klinger, Barry A., Drijfhout, Sybren, Marotzke, Jochem and Scott, Jeffery R. (2004) Remote wind-driven overturning in the absence of the Drake Passage Effect. Journal of Physical Oceanography, 34 (5), 1036-1049. (doi:10.1175/1520-0485(2004)034<1036:RWOITA>2.0.CO;2).

Record type: Article

Abstract

Zonal wind stress over the Southern Ocean may be responsible for a significant fraction of the meridional overturning associated with North Atlantic Deep Water. Numerical experiments by Tsujino and Suginohara imply that the zonal periodicity of the Southern Ocean is not necessary for midlatitude westerly winds to drive strong remote meridional overturning. Here, idealized numerical experiments examine the importance of zonal periodicity and other factors in setting the sensitivity of this overturning to the wind stress. These experiments support the conclusion that the wind can drive remote overturning in the absence of zonal periodicity. However, making the subpolar ocean zonally periodic roughly doubles the strength of the overturning induced by the wind there. Tsujino and Suginohara's experiments are especially sensitive to wind stress because their basin has a relatively small meridional range, which increases the Ekman transport associated with the wind stress. Depending on the stratification in the wind-forcing region, the heating associated with the westerly winds can occur almost exclusively near the surface or deeper in the thermocline as well. Subsurface cooling in the wind-forcing region reduces the remote effects and can occur through both vertical or horizontal diffusion. A scale analysis of the heat budget suggests that sufficiently strong subpolar westerlies produce remote overturning because there is no way for local cooling to balance wind-induced surface heating. Tsujino and Suginohara suggested that wind increases the overturning by enhancing the mixing-driven thermohaline circulation. However, an increase in thermohaline circulation is associated with increased conversion of turbulent kinetic energy to potential energy. This increase in the energy conversion is absent in the wind-driven case, indicating an important qualitative difference between mixing-driven thermohaline overturning and remote wind-driven overturning.

This record has no associated files available for download.

More information

Published date: May 2004
Organisations: Ocean and Earth Science

Identifiers

Local EPrints ID: 349169
URI: http://eprints.soton.ac.uk/id/eprint/349169
ISSN: 0022-3670
PURE UUID: 141a84cd-590d-4a0b-9d34-f34a7a4c286b

Catalogue record

Date deposited: 26 Feb 2013 11:16
Last modified: 07 Jan 2022 21:25

Export record

Altmetrics

Contributors

Author: Barry A. Klinger
Author: Jochem Marotzke
Author: Jeffery R. Scott

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×