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| Titel |
New insights into fCO2 variability in the tropical eastern Pacific Ocean using SMOS SSS |
| VerfasserIn |
C. Walker Brown, J. Boutin, L. Merlivat |
| 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 ; 12, no. 23 ; Nr. 12, no. 23 (2015-12-14), S.7315-7329 |
| Datensatznummer |
250118213
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| Publikation (Nr.) |
 copernicus.org/bg-12-7315-2015.pdf |
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| Zusammenfassung |
Complex oceanic circulation and air–sea interaction make the eastern
tropical Pacific Ocean (ETPO) a highly variable source of CO2 to the
atmosphere. Although the scientific community have amassed 70 000 surface
fugacities of carbon dioxide (fCO2) data points within the ETPO region
over the past 25 years, the spatial and temporal resolution of this data set
is insufficient to fully quantify the seasonal to interannual variability
of the region, a region where fCO2 has been observed to fluctuate by
> 300 μatm.
Upwelling and rainfall events dominate the surface physical and chemical
characteristics of the ETPO, with both yielding unique signatures in sea
surface temperature and salinity. Thus, we explore the potential of using a
statistical description of fCO2 within sea-surface salinity–temperature
space. These SSS/SST relationships are based on in situ surface
ocean CO2 atlas (SOCAT) data collected within the ETPO. This statistical description is then applied to high-resolution (0.25°) Soil
Moisture and Ocean Salinity (SMOS) sea surface salinity (SSS) and Operational Sea
Surface Temperature and Sea Ice Analysis (OSTIA) sea
surface temperature (SST) in order to compute regional fCO2. As a result, we
are able to resolve fCO2 at sufficiently high resolution to elucidate
the influence that various physical processes have on the fCO2 of the
surface ETPO.
Normalised (to 2014) oceanic fCO2 between July 2010 and June 2014
within the entire ETPO was 39 (±10.7) μatm supersaturated with respect to 2014
atmospheric partial pressures, and featured a CO2 outgassing of 1.51
(±0.41) mmol m−2 d−1. Values of fCO2 within the ETPO
were found to be broadly split between the Gulf of Panama region and the rest of the tropical eastern Pacific Ocean.
The northwest, central and offshore regions were supersaturated, with
wintertime wind-jet-driven upwelling found to constitute the first-order control on
fCO2 values. This contrasts with the southeastern/Gulf of Panama
region, where heavy rainfall combined with rapid stratification of the upper
water column act to dilute dissolved inorganic carbon, and yield fCO2
values undersaturated with respect to atmospheric fugacities of CO2. |
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