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

Bergen Open Research Archive

Show simple item record Medhaug, Iselin eng Furevik, Tore eng 2011-08-08T12:49:44Z 2011-08-08T12:49:44Z 2011-06-06 eng
dc.identifier.citation Ocean Science 7(3): 389-404 en
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 eng
dc.publisher The University of Bergen en
dc.rights Copyright the authors eng
dc.rights.uri eng
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 eng
dc.type Journal article eng
dc.subject.nsi VDP::Mathematics and natural science: 400::Geosciences: 450::Solid earth physics: 451 eng
dc.rightsHolder The Authors eng
dc.type.version acceptedVersion eng
bora.peerreviewed Peer reviewed eng
bora.cristinID 825920 eng
bibo.doi eng

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