Temporal variability of the anthropogenic CO<sub>2</sub> storage in the Irminger Sea
The anthropogenic CO<sub>2</sub> (C<sub>ant</sub>) estimates from cruises spanning more than two decades (1981–2006) in the Irminger Sea area of the North Atlantic Subpolar Gyre reveal a large variability in the C<sub>ant</sub> storage rates. During the early 1990...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2008-12-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/5/1669/2008/bg-5-1669-2008.pdf |
| Summary: | The anthropogenic CO<sub>2</sub> (C<sub>ant</sub>) estimates from cruises spanning more than two decades (1981–2006) in the Irminger Sea area of the North Atlantic Subpolar Gyre reveal a large variability in the C<sub>ant</sub> storage rates. During the early 1990's, the C<sub>ant</sub> storage rates (2.3±0.6 mol C m<sup>−2</sup> yr<sup>−1</sup>) doubled the average rate for 1981–2006 (1.1±0.1 mol C m<sup>−2</sup> yr<sup>−1</sup>), whilst a remarkable drop to almost half that average followed from 1997 onwards. The C<sub>ant</sub> storage evolution runs parallel to chlorofluorocarbon-12 inventories and is in good agreement with C<sub>ant</sub> uptake rates of increase calculated from sea surface <i>p</i>CO<sub>2</sub> measurements. The contribution of the Labrador Seawater to the total inventory of C<sub>ant</sub> in the Irminger basin dropped from 66% in the early 1990s to 49% in the early 2000s. The North Atlantic Oscillation shift from a positive to a negative phase in 1996 led to a reduction of air-sea heat loss in the Labrador Sea. The consequent convection weakening accompanied by an increase in stratification has lowered the efficiency of the northern North Atlantic CO<sub>2</sub> sink. |
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| ISSN: | 1726-4170 1726-4189 |