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Titel |
Fingerprints of changes in the terrestrial carbon cycle in response to large reorganizations in ocean circulation |
VerfasserIn |
A. Bozbiyik, M. Steinacher, F. Joos, T. F. Stocker, L. Menviel |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1814-9324
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Digitales Dokument |
URL |
Erschienen |
In: Climate of the Past ; 7, no. 1 ; Nr. 7, no. 1 (2011-03-28), S.319-338 |
Datensatznummer |
250004414
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Publikation (Nr.) |
copernicus.org/cp-7-319-2011.pdf |
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Zusammenfassung |
CO2 and carbon cycle changes in the land, ocean and atmosphere are
investigated using the comprehensive carbon cycle-climate model NCAR
CSM1.4-carbon. Ensemble simulations are forced with freshwater perturbations
applied at the North Atlantic and Southern Ocean deep water formation sites
under pre-industrial climate conditions. As a result, the Atlantic Meridional
Overturning Circulation reduces in each experiment to varying degrees. The
physical climate fields show changes qualitatively in agreement with results documented in the
literature, but there is a clear distinction between northern and southern
perturbations. Changes in the physical variables, in turn, affect the land
and ocean biogeochemical cycles and cause a reduction, or an increase, in the
atmospheric CO2 concentration by up to 20 ppmv, depending on the location of the
perturbation. In the case of a North Atlantic perturbation, the land
biosphere reacts with a strong reduction in carbon stocks in some tropical
locations and in high northern latitudes. In contrast, land carbon stocks
tend to increase in response to a southern perturbation. The ocean is
generally a sink of carbon although large reorganizations occur throughout
various basins. The response of the land biosphere is strongest in the
tropical regions due to a shift of the Intertropical Convergence Zone. The
carbon fingerprints of this shift, either to the south or to the north
depending on where the freshwater is applied, can be found most clearly in
South America. For this reason, a compilation of various paleoclimate proxy
records of Younger Dryas precipitation changes are compared with our model
results. The proxy records, in general, show good agreement with the model's
response to a North Atlantic freshwater perturbation. |
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