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| Titel |
Inter-annual variability of the carbon dioxide oceanic sink south of Tasmania |
| VerfasserIn |
A. V. Borges, B. Tilbrook, N. Metzl, A. Lenton, B. Delille |
| 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 ; 5, no. 1 ; Nr. 5, no. 1 (2008-02-06), S.141-155 |
| Datensatznummer |
250002234
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| Publikation (Nr.) |
 copernicus.org/bg-5-141-2008.pdf |
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| Zusammenfassung |
| We compiled a large data-set from 22 cruises spanning
from 1991 to 2003, of the partial pressure of CO2 (pCO2) in
surface waters over the continental shelf (CS) and adjacent open ocean
(43° to 46° S; 145° to 150° E), south of Tasmania.
Climatological seasonal cycles of pCO2 in the CS, the subtropical zone
(STZ) and the subAntarctic zone (SAZ) are described and used to determine
monthly pCO2 anomalies. These are used in combination with monthly
anomalies of sea surface temperature (SST) to investigate inter-annual
variations of SST and pCO2. Monthly anomalies of SST (as intense as
2°C) are apparent in the CS, STZ and SAZ, and are indicative of strong
inter-annual variability that seems to be related to large-scale coupled
atmosphere-ocean oscillations. Anomalies of pCO2 normalized to a
constant temperature are negatively related to SST anomalies. A reduced
winter-time vertical input of dissolved inorganic carbon (DIC) during phases
of positive SST anomalies, related to a poleward shift of westerly winds,
and a concomitant local decrease in wind stress is the likely cause of the
negative relationship between pCO2 and SST anomalies. The observed
pattern is an increase of the sink for atmospheric CO2 associated with
positive SST anomalies, although strongly modulated by inter-annual
variability of wind speed. Assuming that phases of positive SST anomalies
are indicative of the future evolution of regional ocean biogeochemistry
under global warming, we show using a purely observational based approach
that some provinces of the Southern Ocean could provide a potential negative
feedback on increasing atmospheric CO2. |
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