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| Titel |
The North Atlantic anthropogenic carbon conveyor: temporal variability of
within-ocean transports and their sensitivity to the meridional overturning
circulation |
| VerfasserIn |
Peter Brown, Elaine McDonagh, Richard Sanders, Brian King, David Smeed, Andrew Watson, Ute Schuster, Molly Baringer, Rik Wanninkhof, Chris Meinen |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250133431
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| Publikation (Nr.) |
 EGU/EGU2016-14042.pdf |
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| Zusammenfassung |
| The North Atlantic plays a critical role in the global carbon cycle both as a region of
substantial air-sea carbon dioxide uptake and as a location for the transfer of CO2 to depth on
climatically-important timescales. However, while surface flux variability is relatively well
constrained, our understanding of the changing deep carbon distribution is restricted to
sub-decadal repeat hydrographic sections, and for anthropogenic carbon (Canth), integrated
multi-decadal basin-scale estimates.
Here, we present the first observation-derived high-resolution estimate of short-term
meridional carbon transport variability and long-term trends across the subtropical North
Atlantic. Historical hydrographic data-based estimates of Canth are used to generate
predictive regressions that, combined with RAPID mooring and ARGO float-derived
transport estimates, create a 10-day frequency interior ocean carbon flux time-series for
2004-2012.
The mean net Canth transport across this timeframe is found to be relatively independent
of calculation method and robust at 0.18 PgC yr−1 northwards, with poleward advection of
high Canthshallow waters outweighing the predominantly southwards transports of low
concentrations at depth. Substantial seasonal, sub-annual and interannual transport variability
is observed that is highly sensitive to the strength of the overturning circulation. While the
recently identified multi-year decrease in MOC strength similarly impacts Canth transports,
its full effect is masked by the northwards transport of increasing surface Canth
levels. A comparison with historical estimates of the regional carbon sink reveals an
intrinsic relationship between air-sea uptake, ocean transport and heat fluxes, which
will become more important as the ocean responds to a changing global climate. |
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