Trends of anthropogenic CO<sub>2</sub> storage in North Atlantic water masses
A high-quality inorganic carbon system database, spanning over three decades (1981–2006) and comprising of 13 cruises, has allowed the applying of the <i>φ</i>C°<sub><i>T</i></sub> method and coming up with estimates of the anthropogenic CO<sub&...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2010-05-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/7/1789/2010/bg-7-1789-2010.pdf |
| _version_ | 1811246189558890496 |
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| author | P. Lherminier A. Velo H. Mercier M. Vázquez-Rodríguez F. F. Pérez A. F. Ríos |
| author_facet | P. Lherminier A. Velo H. Mercier M. Vázquez-Rodríguez F. F. Pérez A. F. Ríos |
| author_sort | P. Lherminier |
| collection | DOAJ |
| description | A high-quality inorganic carbon system database, spanning over three decades (1981–2006) and comprising of 13 cruises, has allowed the applying of the <i>φ</i>C°<sub><i>T</i></sub> method and coming up with estimates of the anthropogenic CO<sub>2</sub> (<i>C</i><sub>ant</sub>) stored in the main water masses of the North Atlantic. In the studied region, strong convective processes convey surface properties, like <i>C</i><sub>ant</sub>, into deeper ocean layers and grants this region an added oceanographic interest from the point of view of air-sea CO<sub>2</sub> exchanges. Generally, a tendency for decreasing <i>C</i><sub>ant</sub> storage rates towards the deep layers has been observed. In the Iberian Basin, the North Atlantic Deep Water has low <i>C</i><sub>ant</sub> concentrations and negligible storage rates, while the North Atlantic Central Water in the upper layers shows the largest <i>C</i><sub>ant</sub> values and the largest annual increase of its average concentration (1.13 ± 0.14 μmol kg<sup>−1</sup> yr<sup>−1</sup>). This unmatched rate of change in the <i>C</i><sub>ant</sub> concentration of the warm upper limb of the Meridional Overturning Circulation decreases towards the Irminger basin (0.68 ± 0.06 μmol kg<sup>−1</sup> yr<sup>−1</sup>) due to the lowering of the buffering capacity. The mid and deep waters in the Irminger Sea show rather similar <i>C</i><sub>ant</sub> concentration rates of increase (between 0.33 and 0.45 μmol kg<sup>−1</sup> yr<sup>−1</sup>), whereas in the Iceland basin these layers seem to have been less affected by <i>C</i><sub>ant</sub>. Overall, the <i>C</i><sub>ant</sub> 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 CO<sub>2</sub> 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 CO<sub>2</sub> sink. |
| first_indexed | 2024-04-12T14:50:04Z |
| format | Article |
| id | doaj.art-c57a86158bdf4138b5eddd0c5d027765 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-04-12T14:50:04Z |
| publishDate | 2010-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-c57a86158bdf4138b5eddd0c5d0277652022-12-22T03:28:30ZengCopernicus PublicationsBiogeosciences1726-41701726-41892010-05-01751789180710.5194/bg-7-1789-2010Trends of anthropogenic CO<sub>2</sub> storage in North Atlantic water massesP. LherminierA. VeloH. MercierM. Vázquez-RodríguezF. F. PérezA. F. RíosA high-quality inorganic carbon system database, spanning over three decades (1981–2006) and comprising of 13 cruises, has allowed the applying of the <i>φ</i>C°<sub><i>T</i></sub> method and coming up with estimates of the anthropogenic CO<sub>2</sub> (<i>C</i><sub>ant</sub>) stored in the main water masses of the North Atlantic. In the studied region, strong convective processes convey surface properties, like <i>C</i><sub>ant</sub>, into deeper ocean layers and grants this region an added oceanographic interest from the point of view of air-sea CO<sub>2</sub> exchanges. Generally, a tendency for decreasing <i>C</i><sub>ant</sub> storage rates towards the deep layers has been observed. In the Iberian Basin, the North Atlantic Deep Water has low <i>C</i><sub>ant</sub> concentrations and negligible storage rates, while the North Atlantic Central Water in the upper layers shows the largest <i>C</i><sub>ant</sub> values and the largest annual increase of its average concentration (1.13 ± 0.14 μmol kg<sup>−1</sup> yr<sup>−1</sup>). This unmatched rate of change in the <i>C</i><sub>ant</sub> concentration of the warm upper limb of the Meridional Overturning Circulation decreases towards the Irminger basin (0.68 ± 0.06 μmol kg<sup>−1</sup> yr<sup>−1</sup>) due to the lowering of the buffering capacity. The mid and deep waters in the Irminger Sea show rather similar <i>C</i><sub>ant</sub> concentration rates of increase (between 0.33 and 0.45 μmol kg<sup>−1</sup> yr<sup>−1</sup>), whereas in the Iceland basin these layers seem to have been less affected by <i>C</i><sub>ant</sub>. Overall, the <i>C</i><sub>ant</sub> 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 CO<sub>2</sub> 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 CO<sub>2</sub> sink.http://www.biogeosciences.net/7/1789/2010/bg-7-1789-2010.pdf |
| spellingShingle | P. Lherminier A. Velo H. Mercier M. Vázquez-Rodríguez F. F. Pérez A. F. Ríos Trends of anthropogenic CO<sub>2</sub> storage in North Atlantic water masses Biogeosciences |
| title | Trends of anthropogenic CO<sub>2</sub> storage in North Atlantic water masses |
| title_full | Trends of anthropogenic CO<sub>2</sub> storage in North Atlantic water masses |
| title_fullStr | Trends of anthropogenic CO<sub>2</sub> storage in North Atlantic water masses |
| title_full_unstemmed | Trends of anthropogenic CO<sub>2</sub> storage in North Atlantic water masses |
| title_short | Trends of anthropogenic CO<sub>2</sub> storage in North Atlantic water masses |
| title_sort | trends of anthropogenic co sub 2 sub storage in north atlantic water masses |
| url | http://www.biogeosciences.net/7/1789/2010/bg-7-1789-2010.pdf |
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