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| Titel |
Seasonal variations of sea–air CO2 fluxes in the largest tropical marginal sea (South China Sea) based on multiple-year underway measurements |
| VerfasserIn |
W.-D. Zhai, M.-H. Dai, B.-S. Chen, X.-H. Guo, Q. Li, S.-L. Shang, C.-Y. Zhang, W.-J. Cai, D.-X. Wang |
| 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 ; 10, no. 11 ; Nr. 10, no. 11 (2013-11-29), S.7775-7791 |
| Datensatznummer |
250085448
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| Publikation (Nr.) |
 copernicus.org/bg-10-7775-2013.pdf |
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| Zusammenfassung |
| Based upon 14 field surveys conducted between 2003 and 2008, we showed
that the seasonal pattern of sea surface partial pressure of CO2
(pCO2) and sea–air CO2 fluxes differed among four different
physical–biogeochemical domains in the South China Sea (SCS) proper. The four
domains were located between 7 and 23° N and 110 and
121° E, covering a surface area of
1344 × 103 km2 and accounting for ~ 54% of the
SCS proper. In the area off the Pearl River estuary, relatively low
pCO2 values of 320 to 390 μatm were observed in all four
seasons and both the biological productivity and CO2 uptake were
enhanced in summer in the Pearl River plume waters. In the northern SCS
slope/basin area, a typical seasonal cycle of relatively high pCO2 in
the warm seasons and relatively low pCO2 in the cold seasons was
revealed. In the central/southern SCS area, moderately high sea surface
pCO2 values of 360 to 425 μatm were observed throughout the
year. In the area west of the Luzon Strait, a major exchange pathway between
the SCS and the Pacific Ocean, pCO2 was particularly dynamic in
winter, when northeast monsoon induced upwelling events and strong outgassing
of CO2. These episodic events might have dominated the annual sea–air
CO2 flux in this particular area. The estimate of annual sea–air
CO2 fluxes showed that most areas of the SCS proper served as weak to
moderate sources of the atmospheric CO2, with sea–air CO2 flux
values of 0.46 ± 0.43 mol m−2 yr−1 in the northern SCS
slope/basin, 1.37 ± 0.55 mol m−2 yr−1 in the
central/southern SCS, and 1.21 ± 1.48 mol m−2 yr−1 in the
area west of the Luzon Strait. However, the annual sea–air CO2 exchange
was nearly in equilibrium (−0.44 ± 0.65 mol m−2 yr−1) in
the area off the Pearl River estuary. Overall the four domains contributed
(18 ± 10) × 1012 g C yr−1 to the atmospheric
CO2. |
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