The University of Southampton
University of Southampton Institutional Repository

Physical and biogeochemical fluxes and net budgets in the subpolar and temperate North Atlantic

Physical and biogeochemical fluxes and net budgets in the subpolar and temperate North Atlantic
Physical and biogeochemical fluxes and net budgets in the subpolar and temperate North Atlantic
A transoceanic hydrographic section across the North Atlantic Subpolar gyre from Vigo (northwestern Iberian Peninsula) to Cape Farewell (south of Greenland) was sampled in summer 1997 as part of the World Ocean Circulation Experiment program (WOCE A25, 4x cruise). The circulation pattern across the 4x section is diagnosed using inverse methods. The flow is constrained with measured mass transports at specific sites, while conserving mass and salt for the region north of the section and forcing the silicate flux to a reasonable value. The fluxes of physical (heat and freshwater) and chemical (nutrients and oxygen) properties are estimated and decomposed into barotropic, baroclinic and horizontal components. The heat transport amounts to 0.65 ± 0.1 PW poleward, with 54% and 45% of the flux due to the baroclinic (or overturning) and horizontal circulation, respectively. From the salt conservation, an equatorward freshwater transport of-0.4 ± 1.5 Sv is estimated, resulting from net precipitation plus runoff over the North Atlantic Ocean north of the section. The Subpolar gyre exports nutrients and oxygen southward toward the Subtropical ocean at rates of -50 ± 19, -6 ± 2, -26 ± 15 and -1992 ± 440 kmol s-1 for nitrate, phosphate, silicate and oxygen, respectively. The main mechanism responsible for the nutrient transport is the overturning cell, whereas oxygen is mainly transported southward due to the large-scale horizontal circulation. Combining our fluxes with those from the 36N section (Rintoul and Wunsch, 1991) allows us to examine budgets of physical (heat and freshwater) and chemical (nitrogen and oxygen) properties for an enclosed area of the Subpolar and Temperate North Atlantic. The tentative nitrogen budget for the box between the 4x and the 36N sections suggests that the Temperate North Atlantic is exporting organic nitrogen toward the Subtropical and the Subpolar provinces, which is consistent with indirect evidence.
NORTH ATLANTIC, ATLN, CIRCULATION PATTERNS, HEAT FLUX, FRESHWATER FLUX, NITROGEN CYCLE, OXYGEN
0022-2402
191-226
Alvarez, M.
7be56f04-a66d-4f65-bc81-bc0e47607729
Bryden, H.L.
7f823946-34e8-48a3-8bd4-a72d2d749184
Perez, F.F.
f8d4789c-1a2e-470c-bdcd-c0f05c3afabf
Rios, A.F.
dd6720b0-bd7a-4849-9ebe-020864db8fa7
Roson, G.
9682e5a7-6a42-404e-931e-45cf5c382feb
Alvarez, M.
7be56f04-a66d-4f65-bc81-bc0e47607729
Bryden, H.L.
7f823946-34e8-48a3-8bd4-a72d2d749184
Perez, F.F.
f8d4789c-1a2e-470c-bdcd-c0f05c3afabf
Rios, A.F.
dd6720b0-bd7a-4849-9ebe-020864db8fa7
Roson, G.
9682e5a7-6a42-404e-931e-45cf5c382feb

Alvarez, M., Bryden, H.L., Perez, F.F., Rios, A.F. and Roson, G. (2002) Physical and biogeochemical fluxes and net budgets in the subpolar and temperate North Atlantic. Journal of Marine Research, 60 (2), 191-226. (doi:10.1357/00222400260497462).

Record type: Article

Abstract

A transoceanic hydrographic section across the North Atlantic Subpolar gyre from Vigo (northwestern Iberian Peninsula) to Cape Farewell (south of Greenland) was sampled in summer 1997 as part of the World Ocean Circulation Experiment program (WOCE A25, 4x cruise). The circulation pattern across the 4x section is diagnosed using inverse methods. The flow is constrained with measured mass transports at specific sites, while conserving mass and salt for the region north of the section and forcing the silicate flux to a reasonable value. The fluxes of physical (heat and freshwater) and chemical (nutrients and oxygen) properties are estimated and decomposed into barotropic, baroclinic and horizontal components. The heat transport amounts to 0.65 ± 0.1 PW poleward, with 54% and 45% of the flux due to the baroclinic (or overturning) and horizontal circulation, respectively. From the salt conservation, an equatorward freshwater transport of-0.4 ± 1.5 Sv is estimated, resulting from net precipitation plus runoff over the North Atlantic Ocean north of the section. The Subpolar gyre exports nutrients and oxygen southward toward the Subtropical ocean at rates of -50 ± 19, -6 ± 2, -26 ± 15 and -1992 ± 440 kmol s-1 for nitrate, phosphate, silicate and oxygen, respectively. The main mechanism responsible for the nutrient transport is the overturning cell, whereas oxygen is mainly transported southward due to the large-scale horizontal circulation. Combining our fluxes with those from the 36N section (Rintoul and Wunsch, 1991) allows us to examine budgets of physical (heat and freshwater) and chemical (nitrogen and oxygen) properties for an enclosed area of the Subpolar and Temperate North Atlantic. The tentative nitrogen budget for the box between the 4x and the 36N sections suggests that the Temperate North Atlantic is exporting organic nitrogen toward the Subtropical and the Subpolar provinces, which is consistent with indirect evidence.

Full text not available from this repository.

More information

Published date: 2002
Keywords: NORTH ATLANTIC, ATLN, CIRCULATION PATTERNS, HEAT FLUX, FRESHWATER FLUX, NITROGEN CYCLE, OXYGEN

Identifiers

Local EPrints ID: 6104
URI: http://eprints.soton.ac.uk/id/eprint/6104
ISSN: 0022-2402
PURE UUID: e11edf4f-c4a9-4ca6-9d81-09a1fe6ae915
ORCID for H.L. Bryden: ORCID iD orcid.org/0000-0002-8216-6359

Catalogue record

Date deposited: 24 Jun 2004
Last modified: 03 Dec 2019 01:59

Export record

Altmetrics

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.

×