Past studies have shown that the feedback of extratropical sea surface temperature on the atmosphere is weak on interannual time scales. However, recent evidence suggests that the long-term variability of the sea surface temperature in the North Atlantic, referred to as Atlantic Multidecadal Variability (AMV), may exert a significant influence on the atmospheric circulation in the Northern Hemisphere. In particular, statistical analyses using observation/reanalyses, as well as numerical experiments using different configurations of the Community Atmospheric Model version 5 (CAM5), suggest that the AMV exerts an influence on decadal trends of the wintertime North Atlantic Oscillation (NAO). Coupled ocean-atmosphere simulations of the Climate Model Intercomparison Project (CMIP5) are examined in order to assess whether the state-of- the-art general circulation models capture such a relationship. Multiyear persistence of the wintertime NAO is a driver of the AMV in these simulations, but no consistent feedback of the AMV onto the atmosphere is identified. Although model-observation comparisons are subject to caution due to large uncertainties in long-term observations, a lack of internally-generated AMV and associated surface heat flux variability in the models seems to limit their ability to capture the full AMV-NAO relationship.
Events that address critical issues confronting society in pursuit of environmental balance, economic vitality & social justice.
Get weekly updates on the Sustainability Events Calendar with the UCI Global Sustainability Resource Center’s Weekly Digest.