Fingerprints of changes in the terrestrial carbon cycle in response to large reorganizations in ocean circulation

Bozbiyik, Anil; Steinacher, Marco; Joos, Fortunato; Stocker, Thomas F.; Menviel, Laurie (2011). Fingerprints of changes in the terrestrial carbon cycle in response to large reorganizations in ocean circulation. Climate of the past, 7(1), pp. 319-338. Göttingen: Copernicus Publications 10.5194/cp-7-319-2011

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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.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Climate and Environmental Physics
08 Faculty of Science > Physics Institute

UniBE Contributor:

Bozbiyik, Anil; Steinacher, Marco; Joos, Fortunat; Stocker, Thomas and Menviel, Laurie

ISSN:

1814-9324

Publisher:

Copernicus Publications

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:27

Last Modified:

06 Dec 2014 14:53

Publisher DOI:

10.5194/cp-7-319-2011

Web of Science ID:

000288992700023

BORIS DOI:

10.7892/boris.10130

URI:

https://boris.unibe.ch/id/eprint/10130 (FactScience: 215972)

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