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Variability of Antarctic Bottom Water at 24.5°N in the Atlantic

Variability of Antarctic Bottom Water at 24.5°N in the Atlantic
Variability of Antarctic Bottom Water at 24.5°N in the Atlantic
A recent hydrographic section at 24.5°N in the Atlantic and 6 months of observations from a moored array show that Antarctic Bottom Water (AABW), the densest and deepest water mass in the world oceans, has been warming. While Johnson et al. (2008) showed that northward AABW transport at 24.5°N has been declining from 1981 to 2004, suggesting that the lower cell of the overturning circulation could halt in the near future, estimates from the latest hydrographic section in 2010 indicate a partial recovery of northward AABW transport. From 6 months of temperature and salinity observations at a deep moored array at 24–26°N, we find that short-term variability between April and November 2009 is of the same magnitude as the changes observed from hydrographic sections between 1981 and 2004. These observations highlight the possibility that transport changes estimated from hydrographic sections may be aliased by short-term variability. The observed AABW transport variability affects present estimates of the upper meridional overturning circulation by ±0.4 Sv (1 Sv = 106 m3 s?1).
antarctic bottom water, deep water transport, ocean circulation
0148-0227
1-11
Frajka-Williams, E.
da86044e-0f68-4cc9-8f60-7fdbc4dc19cb
Cunningham, S.A.
07f1bd78-d92f-478b-a016-b92f530142c3
Bryden, H.
7f823946-34e8-48a3-8bd4-a72d2d749184
King, B.A.
960f44b4-cc9c-4f77-b3c8-775530ac0061
Frajka-Williams, E.
da86044e-0f68-4cc9-8f60-7fdbc4dc19cb
Cunningham, S.A.
07f1bd78-d92f-478b-a016-b92f530142c3
Bryden, H.
7f823946-34e8-48a3-8bd4-a72d2d749184
King, B.A.
960f44b4-cc9c-4f77-b3c8-775530ac0061

Frajka-Williams, E., Cunningham, S.A., Bryden, H. and King, B.A. (2011) Variability of Antarctic Bottom Water at 24.5°N in the Atlantic. Journal of Geophysical Research, 116 (C11), 1-11. (doi:10.1029/2011JC007168).

Record type: Article

Abstract

A recent hydrographic section at 24.5°N in the Atlantic and 6 months of observations from a moored array show that Antarctic Bottom Water (AABW), the densest and deepest water mass in the world oceans, has been warming. While Johnson et al. (2008) showed that northward AABW transport at 24.5°N has been declining from 1981 to 2004, suggesting that the lower cell of the overturning circulation could halt in the near future, estimates from the latest hydrographic section in 2010 indicate a partial recovery of northward AABW transport. From 6 months of temperature and salinity observations at a deep moored array at 24–26°N, we find that short-term variability between April and November 2009 is of the same magnitude as the changes observed from hydrographic sections between 1981 and 2004. These observations highlight the possibility that transport changes estimated from hydrographic sections may be aliased by short-term variability. The observed AABW transport variability affects present estimates of the upper meridional overturning circulation by ±0.4 Sv (1 Sv = 106 m3 s?1).

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e-pub ahead of print date: 17 November 2011
Published date: November 2011
Keywords: antarctic bottom water, deep water transport, ocean circulation
Organisations: Physical Oceanography, Marine Physics and Ocean Climate

Identifiers

Local EPrints ID: 203563
URI: http://eprints.soton.ac.uk/id/eprint/203563
ISSN: 0148-0227
PURE UUID: fdc8b450-9c50-4589-8ef4-230e056d5d53
ORCID for E. Frajka-Williams: ORCID iD orcid.org/0000-0001-8773-7838
ORCID for H. Bryden: ORCID iD orcid.org/0000-0002-8216-6359

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Date deposited: 17 Nov 2011 11:51
Last modified: 15 Mar 2024 03:35

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Contributors

Author: E. Frajka-Williams ORCID iD
Author: S.A. Cunningham
Author: H. Bryden ORCID iD
Author: B.A. King

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