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North Atlantic 20th century multidecadal variability in coupled climate models: sea surface temperature and ocean overturning circulation

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dc.contributor.author Medhaug, Iselin
dc.contributor.author Furevik, Tore
dc.date.accessioned 2011-08-08T12:49:44Z
dc.date.available 2011-08-08T12:49:44Z
dc.date.issued 2011-06-06
dc.identifier.citation Ocean Science 7(3): 389-404 en
dc.identifier.uri http://dx.doi.org/10.5194/os-7-389-2011
dc.identifier.uri http://hdl.handle.net/1956/4868
dc.description.abstract Output from a total of 24 state-of-the-art Atmosphere-Ocean General Circulation Models is analyzed. The models were integrated with observed forcing for the period 1850–2000 as part of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report. All models show enhanced variability at multi-decadal time scales in the North Atlantic sector similar to the observations, but with a large intermodel spread in amplitudes and frequencies for both the Atlantic Multidecadal Oscillation (AMO) and the Atlantic Meridional Overturning Circulation (AMOC). The models, in general, are able to reproduce the observed geographical patterns of warm and cold episodes, but not the phasing such as the early warming (1930s–1950s) and the following colder period (1960s–1980s). This indicates that the observed 20th century extreme in temperatures are due to primarily a fortuitous phasing of intrinsic climate variability and not dominated by external forcing. Most models show a realistic structure in the overturning circulation, where more than half of the available models have a mean overturning transport within the observed estimated range of 13–24 Sverdrup. Associated with a stronger than normal AMOC, the surface temperature is increased and the sea ice extent slightly reduced in the North Atlantic. Individual models show potential for decadal prediction based on the relationship between the AMO and AMOC, but the models strongly disagree both in phasing and strength of the covariability. This makes it difficult to identify common mechanisms and to assess the applicability for predictions. en_US
dc.language.iso eng en_US
dc.publisher The University of Bergen en
dc.rights Copyright the Authors en_US
dc.rights.uri http://creativecommons.org/licenses/by/3.0/ en_US
dc.title North Atlantic 20th century multidecadal variability in coupled climate models: sea surface temperature and ocean overturning circulation en_US
dc.type Peer reviewed en_US
dc.type Journal article en_US
dc.subject.nsi VDP::Mathematics and natural science: 400::Geosciences: 450::Solid earth physics: 451 en_US
dc.rightsHolder The Authors en_US
dc.type.version acceptedVersion en_US
bora.cristinID 825920 en


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