Low-frequency oscillations of the Atlantic Ocean meridional overturning circulation in a coupled climate model
Using a 3-dimensional climate model of intermediatecomplexity we show that the overturning circulation ofthe Atlantic Ocean can vary at multicentennial-to-millennialtimescales for modern boundary conditions. A continuousfreshwater perturbation in the Labrador Sea pushes the overturningcirculation of...
| Main Authors: | , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus Gesellschaft MBH
2007
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| Subjects: | |
| Online Access: | http://dx.doi.org/ http://ecite.utas.edu.au/91592 |
| Summary: | Using a 3-dimensional climate model of intermediatecomplexity we show that the overturning circulation ofthe Atlantic Ocean can vary at multicentennial-to-millennialtimescales for modern boundary conditions. A continuousfreshwater perturbation in the Labrador Sea pushes the overturningcirculation of the Atlantic Ocean into a bi-stableregime, characterized by phases of active and inactive deepwaterformation in the Labrador Sea. In contrast, deep-waterformation in the Nordic Seas is active during all phases ofthe oscillations. The actual timing of the transitions betweenthe two circulation states occurs randomly. The oscillationsconstitute a 3-dimensional phenomenon and have tobe distinguished from low-frequency oscillations seen previouslyin 2-dimensional models of the ocean. A conceptualmodel provides further insight into the essential dynamicsunderlying the oscillations of the large-scale ocean circulation.The model experiments indicate that the coupledclimate system can exhibit unforced climate variability atmulticentennial-to-millennial timescales that may be of relevancefor Holocene climate variations. |
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