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| Titel |
Trends of anthropogenic CO2 storage in North Atlantic water masses |
| VerfasserIn |
F. F. Pérez, M. Vázquez-Rodríguez, H. Mercier, A. Velo, P. Lherminier, A. F. Ríos |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 5 ; Nr. 7, no. 5 (2010-05-28), S.1789-1807 |
| Datensatznummer |
250004784
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| Publikation (Nr.) |
 copernicus.org/bg-7-1789-2010.pdf |
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| Zusammenfassung |
| A high-quality inorganic carbon system database, spanning over three
decades (1981–2006) and comprising of 13 cruises, has allowed the
applying of the φC°T method and coming up with
estimates of the anthropogenic CO2 (Cant) stored in
the main water masses of the North Atlantic. In the studied region,
strong convective processes convey surface properties, like Cant, into deeper ocean layers and grants this region an added
oceanographic interest from the point of view of air-sea CO2
exchanges. Generally, a tendency for decreasing Cant
storage rates towards the deep layers has been observed. In the
Iberian Basin, the North Atlantic Deep Water has low Cant
concentrations and negligible storage rates, while the North
Atlantic Central Water in the upper layers shows the largest Cant values and the largest annual increase of its average
concentration
(1.13 ± 0.14 μmol kg−1 yr−1). This
unmatched rate of change in the Cant concentration of the
warm upper limb of the Meridional Overturning Circulation decreases
towards the Irminger basin
(0.68 ± 0.06 μmol kg−1 yr−1) due to the
lowering of the buffering capacity. The mid and deep waters in the
Irminger Sea show rather similar Cant concentration rates
of increase (between 0.33 and
0.45 μmol kg−1 yr−1), whereas in the Iceland
basin these layers seem to have been less affected by Cant.
Overall, the Cant storage rates in the North Atlantic
subpolar gyre during the first half of the 1990s, when a high North
Atlantic Oscillation (NAO) phase was dominant, are ~48%
higher than during the 1997–2006 low NAO phase that followed. This
result suggests that a net decrease in the strength of the North
Atlantic sink of atmospheric CO2 has taken place during the
present decade. The changes in deep-water ventilation are the main
driving processes causing this weakening of the North Atlantic
CO2 sink. |
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