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Titel |
Observed decline of the Atlantic meridional overturning circulation 2004-2012 |
VerfasserIn |
D. A. Smeed, G. D. McCarthy, S. A. Cunningham, E. Frajka-Williams, D. Rayner, W. E. Johns, C. S. Meinen, M. O. Baringer, B. I. Moat, A. Duchez, H. L. Bryden |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1812-0784
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Digitales Dokument |
URL |
Erschienen |
In: Ocean Science ; 10, no. 1 ; Nr. 10, no. 1 (2014-02-06), S.29-38 |
Datensatznummer |
250116921
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Publikation (Nr.) |
copernicus.org/os-10-29-2014.pdf |
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Zusammenfassung |
The Atlantic meridional overturning circulation (AMOC) has been observed
continuously at 26° N since April 2004. The AMOC and its component
parts are monitored by combining a transatlantic array of moored instruments
with submarine-cable-based measurements of the Gulf Stream and satellite
derived Ekman transport. The time series has recently been extended to
October 2012 and the results show a downward trend since 2004. From
April 2008 to March 2012, the AMOC was an average of 2.7 Sv
(1 Sv = 106 m3 s−1) weaker than in the first four years
of observation (95% confidence that the reduction is 0.3 Sv or more).
Ekman transport reduced by about 0.2 Sv and the Gulf Stream by 0.5 Sv but
most of the change (2.0 Sv) is due to the mid-ocean geostrophic flow. The
change of the mid-ocean geostrophic flow represents a strengthening of the
southward flow above the thermocline. The increased southward flow of warm
waters is balanced by a decrease in the southward flow of lower North
Atlantic deep water below 3000 m. The transport of lower North Atlantic deep
water slowed by 7% per year (95% confidence that the rate of
slowing is greater than 2.5% per year). |
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