Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes

An annual-mean surface-forced component of the North Atlantic thermohaline circulation (THC) in density space, surf(,?), is diagnosed from observed surface heat and freshwater fluxes. The climatological mean of surf over 1980–97 indicates steady overturning rates for those water masses that are prin...

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Main Author: Marsh, R.
Format: Article in Journal/Newspaper
Language:unknown
Published: 2000
Subjects:
Online Access:https://eprints.soton.ac.uk/8909/
http://ams.allenpress.com/amsonline/?request=get-abstract&issn=1520-0442&volume=013&issue=18&page=3239
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spelling ftsouthampton:oai:eprints.soton.ac.uk:8909 2023-07-30T04:02:10+02:00 Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes Marsh, R. 2000 https://eprints.soton.ac.uk/8909/ http://ams.allenpress.com/amsonline/?request=get-abstract&issn=1520-0442&volume=013&issue=18&page=3239 unknown Marsh, R. (2000) Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes. Journal of Climate, 13 (18), 3239-3260. (doi:10.1175/1520-0442(2000)013<3239:RVOTNA>2.0.CO;2 <http://dx.doi.org/10.1175/1520-0442(2000)013<3239:RVOTNA>2.0.CO;2>). Article PeerReviewed 2000 ftsouthampton https://doi.org/10.1175/1520-0442(2000)013<3239:RVOTNA>2.0.CO;2 2023-07-09T20:29:36Z An annual-mean surface-forced component of the North Atlantic thermohaline circulation (THC) in density space, surf(,?), is diagnosed from observed surface heat and freshwater fluxes. The climatological mean of surf over 1980–97 indicates steady overturning rates for those water masses that are principally formed through surface buoyancy forcing: 8 Sv of Greenland Sea Deep Water (GSDW), 4 Sv of Labrador Sea Water (LSW), and 4 Sv of 18° Water (STMW). Obtained for each year over 1980–97, surf reveals interannual-to-decadal variability in the renewal and overturning of these water masses. The total surface-forced overturning rate varies in the range 10–20 Sv, reaching peak values in 1989–90 and generally decreasing over the period 1990–97. More dramatic changes are apparent in the overturning of different water masses. The overturning of STMW exhibits large-amplitude interannual variability. A background positive trend over 1980–97 is dominated by variance of 13.4 Sv. By contrast, the overturning rates of LSW and GSDW vary more slowly, on decadal timescales. LSW overturning rates increase from near zero in the early 1980s to a maximum of 10 Sv in 1990 and return to near zero by 1997. Seemingly in antiphase, GSDW overturning rates decline from a peak rate of 11 Sv in 1981 to a minimum of 3.5 Sv in 1991, and then increase somewhat up to 1997. The variability in these overturning rates is related to changes in the North Atlantic oscillation (NAO) and the Arctic oscillation (AO) over 1980–97. Correlation coefficients between total overturning rate and three versions of the NAO index are significantly positive at a 99% confidence level. Also highly significant is a correlation of LSW overturning and the AO index, and an anticorrelation between overturning of LSW and GSDW. The overturning of STMW is more weakly (and not significantly) anticorrelated with NAO indices, although there is highly significant anticorrelation between interannual changes in STMW overturning and one version of the NAO index. Stronger LSW (GSDW) ... Article in Journal/Newspaper Arctic Greenland Greenland Sea Labrador Sea North Atlantic North Atlantic oscillation North atlantic Thermohaline circulation University of Southampton: e-Prints Soton Arctic Greenland
institution Open Polar
collection University of Southampton: e-Prints Soton
op_collection_id ftsouthampton
language unknown
description An annual-mean surface-forced component of the North Atlantic thermohaline circulation (THC) in density space, surf(,?), is diagnosed from observed surface heat and freshwater fluxes. The climatological mean of surf over 1980–97 indicates steady overturning rates for those water masses that are principally formed through surface buoyancy forcing: 8 Sv of Greenland Sea Deep Water (GSDW), 4 Sv of Labrador Sea Water (LSW), and 4 Sv of 18° Water (STMW). Obtained for each year over 1980–97, surf reveals interannual-to-decadal variability in the renewal and overturning of these water masses. The total surface-forced overturning rate varies in the range 10–20 Sv, reaching peak values in 1989–90 and generally decreasing over the period 1990–97. More dramatic changes are apparent in the overturning of different water masses. The overturning of STMW exhibits large-amplitude interannual variability. A background positive trend over 1980–97 is dominated by variance of 13.4 Sv. By contrast, the overturning rates of LSW and GSDW vary more slowly, on decadal timescales. LSW overturning rates increase from near zero in the early 1980s to a maximum of 10 Sv in 1990 and return to near zero by 1997. Seemingly in antiphase, GSDW overturning rates decline from a peak rate of 11 Sv in 1981 to a minimum of 3.5 Sv in 1991, and then increase somewhat up to 1997. The variability in these overturning rates is related to changes in the North Atlantic oscillation (NAO) and the Arctic oscillation (AO) over 1980–97. Correlation coefficients between total overturning rate and three versions of the NAO index are significantly positive at a 99% confidence level. Also highly significant is a correlation of LSW overturning and the AO index, and an anticorrelation between overturning of LSW and GSDW. The overturning of STMW is more weakly (and not significantly) anticorrelated with NAO indices, although there is highly significant anticorrelation between interannual changes in STMW overturning and one version of the NAO index. Stronger LSW (GSDW) ...
format Article in Journal/Newspaper
author Marsh, R.
spellingShingle Marsh, R.
Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes
author_facet Marsh, R.
author_sort Marsh, R.
title Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes
title_short Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes
title_full Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes
title_fullStr Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes
title_full_unstemmed Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes
title_sort recent variability of the north atlantic thermohaline circulation inferred from surface heat and freshwater fluxes
publishDate 2000
url https://eprints.soton.ac.uk/8909/
http://ams.allenpress.com/amsonline/?request=get-abstract&issn=1520-0442&volume=013&issue=18&page=3239
geographic Arctic
Greenland
geographic_facet Arctic
Greenland
genre Arctic
Greenland
Greenland Sea
Labrador Sea
North Atlantic
North Atlantic oscillation
North atlantic Thermohaline circulation
genre_facet Arctic
Greenland
Greenland Sea
Labrador Sea
North Atlantic
North Atlantic oscillation
North atlantic Thermohaline circulation
op_relation Marsh, R. (2000) Recent variability of the North Atlantic thermohaline circulation inferred from surface heat and freshwater fluxes. Journal of Climate, 13 (18), 3239-3260. (doi:10.1175/1520-0442(2000)013<3239:RVOTNA>2.0.CO;2 <http://dx.doi.org/10.1175/1520-0442(2000)013<3239:RVOTNA>2.0.CO;2>).
op_doi https://doi.org/10.1175/1520-0442(2000)013<3239:RVOTNA>2.0.CO;2
_version_ 1772812898650816512