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| Titel |
Mechanisms of forced AMOC variability in a state of the art climate model |
| VerfasserIn |
Matthew Menary, Christopher Roberts, Matthew Palmer, Paul Halloran, Laura Jackson, Richard Wood, Wolfgang Mueller, Daniela Matei, Sang-Ki Lee |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076851
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| Zusammenfassung |
| Mechanisms of sustained multidecadal changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) are investigated in a set of simulations with a new state-of-the-art climate model. Anthropogenic aerosols have previously been highlighted as a potential mitigator of AMOC weakening. In this study, we explain the oceanic mechanisms behind how anthropogenic aerosols could force a strengthening of the AMOC by up to 20% in our state of the art earth system model. This strengthening is driven via atmospheric circulation changes which subsequently modulate the salinity budget of the North Atlantic subpolar gyre. Gradual salinification occurs via increased evaporation and decreased fluxes of freshwater as ice through the Fram Straits. There is also a component of the salinification representing a positive feedback of the AMOC bringing more saline water northwards from the tropical Atlantic. Salinification of the subpolar gyre results in increased deep convection and a strengthening of the AMOC. Following a reduction in aerosol concentrations, the AMOC rapidly weakens, approximately three times faster than in the case where anthropogenic aerosol concentrations had never been increased. Similarities and differences with the available observational record and long term reanalysis products are also discussed. |
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