Climate impacts on multidecadal pCO2 variability in the North Atlantic: 1948–2009
The North Atlantic is the most intense region of ocean CO 2 uptake in term of units per area. Here, we investigate multidecadal timescale variability of the partial pressure of CO 2 ( p CO 2 ) that is due to the natural carbon cycle, using a regional model forced with realistic climate and preindust...
| Published in: | Biogeosciences |
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| Main Authors: | , |
| Format: | Text |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/bg-13-3387-2016 https://www.biogeosciences.net/13/3387/2016/ |
| Summary: | The North Atlantic is the most intense region of ocean CO 2 uptake in term of units per area. Here, we investigate multidecadal timescale variability of the partial pressure of CO 2 ( p CO 2 ) that is due to the natural carbon cycle, using a regional model forced with realistic climate and preindustrial atmospheric p CO 2 for 1948–2009. Large-scale patterns of natural p CO 2 variability are primarily associated with basin-averaged sea surface temperature (SST) that, in turn, is composed of two parts: the Atlantic Multidecadal Oscillation (AMO) and a long-term positive SST trend. The North Atlantic Oscillation (NAO) drives a secondary mode of variability. For the primary mode, positive AMO and the SST trend modify p CO 2 with different mechanisms and spatial patterns. Positive AMO is also associated with a significant reduction in dissolved inorganic carbon (DIC) in the subpolar gyre, due primarily to reduced vertical mixing; the net impact of positive AMO is to reduce p CO 2 in the subpolar gyre. Through direct impacts on SST, the net effect of positive AMO is to increase p CO 2 in the subtropical gyre. From 1980 to present, long-term SST warming has amplified AMO impacts on p CO 2 . |
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