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| Titel |
Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO model |
| VerfasserIn |
V. N. Stepanov, K. Haines |
| 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. 4 ; Nr. 10, no. 4 (2014-07-14), S.645-656 |
| Datensatznummer |
250117037
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| Publikation (Nr.) |
 copernicus.org/os-10-645-2014.pdf |
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| Zusammenfassung |
We have investigated mechanisms for the Atlantic Meridional Overturning
Circulation (AMOC) variability at 26.5° N (other than the Ekman
component) that can be related to external forcings, in particular wind
variability. Resolution dependence is studied using identical experiments
with 1° and 1/4° NEMO model runs over 1960–2010.
The analysis shows that much of the variability in the AMOC at
26° N can be related to the wind strength over the North Atlantic, through
mechanisms lagged on different timescales. At ~ 1-year lag the
January–June difference of mean sea level pressure between high and
mid-latitudes in the North Atlantic explains 35–50% of the interannual
AMOC variability (with negative correlation between wind strength and AMOC).
At longer lead timescales ~ 4 years, strong (weak) winds over the
northern North Atlantic (specifically linked to the NAO index) are followed
by higher (lower) AMOC transport, but this mechanism only works in the
1/4° model. Analysis of the density correlations suggests an increase
(decrease) in deep water formation in the North Atlantic subpolar gyre to be
the cause. Therefore another 30% of the AMOC variability at 26° N can be
related to density changes in the top 1000 m in the Labrador and Irminger
seas occurring ~ 4 years earlier. |
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