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| Titel |
Estimation of the oceanic pCO2 in the North Atlantic from VOS lines in-situ measurements: parameters needed to generate seasonally mean maps |
| VerfasserIn |
C. Jamet, C. Moulin, N. Lefèvre |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 25, no. 11 ; Nr. 25, no. 11 (2007-11-29), S.2247-2257 |
| Datensatznummer |
250015938
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| Publikation (Nr.) |
 copernicus.org/angeo-25-2247-2007.pdf |
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| Zusammenfassung |
| Automated instruments on board Volunteer Observing Ships (VOS) have provided
high-frequency pCO2 measurements over basin-wide regions for a decade
or so. In order to estimate regional air-sea CO2 fluxes, it is
necessary to interpolate between in-situ measurements to obtain maps of the
marine pCO2. Such an interpolation remains, however, a difficult task
because VOS lines are too distant from each other to capture the high
pCO2 variability. Relevant physical parameters available at large scale
are thus necessary to serve as a guide to estimate the pCO2 values between
the VOS lines. Satellites do not measure pCO2 but they give access to
parameters related to the processes that control its variability, such as
sea surface temperature (SST). In this paper we developed a method to
compute pCO2 maps using satellite data (SST and CHL, the chlorophyll
concentration), combined with a climatology of the mixed-layer depth (MLD).
Using 15 401 measurements of surface pCO2 acquired in the North Atlantic
between UK and Jamaica, between June 1994 and August 1995, we show that the
parameterization of pCO2 as a function of SST, CHL and MLD yields more
realistic pCO2 values than parameterizations that have been widely used in the past, based on SST, latitude,
longitude or SST only. This
parameterization was then used to generate seasonal maps of pCO2 over
the North Atlantic. Results show that our approach yields the best marine
pCO2 estimates, both in terms of absolute accuracy, when compared with
an independent data set, and of geographical patterns, when compared to the
climatology of Takahashi et al. (2002). This suggests that monitoring the
seasonal variability of pCO2 over basin-wide regions is possible, provided that sufficient VOS lines are available. |
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