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| Titel |
Sea surface temperature and sub-surface density fingerprints of the AMOC in CMIP5 models |
| VerfasserIn |
Chris Roberts, Freya Garry, Laura Jackson |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091314
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| Publikation (Nr.) |
 EGU/EGU2014-5600.pdf |
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| Zusammenfassung |
| We use simulations from ten coupled climate models to calculate patterns of sea surface temperature (SST) and sub-surface density change associated with decadal AMOC variability. We evaluate models using observational constraints and find that models with a better representation of the AMOC at 26.5 °N also have a better simulation of vertical stratification in the North Atlantic sub-polar gyre. In the models that compare best with observations, positive AMOC anomalies are associated with reduced Labrador Sea stratification and increased mid-ocean (800-1800 m) densities in the sub-polar gyre. Maximum correlations occur when AMOC anomalies lag Labrador Sea stratification and sub-surface density anomalies by 2-6 years and 0-3 years, respectively. In all ten models, North Atlantic warming follows positive AMOC anomalies, but the patterns and magnitudes of SST change are variable. We also evaluate the utility of Atlantic mid-ocean density and Labrador Sea stratification indices for detecting changes to the AMOC in the presence of increasing CO2 concentrations. We find that non-zero trends in mid-ocean density are identifiable (although not attributable) significantly earlier than trends in the AMOC. For this reason, sub-surface density observations could be a useful complement to transport observations made at specific latitudes that may help with the more rapid diagnosis of basin-scale changes in the AMOC. Finally, we conclude that it is not yet possible to detect a robust trend in the AMOC using mid-ocean densities or transport observations from 26.5°N. |
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