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| Titel |
Controls on the spatial distribution of oceanic δ¹³CDIC |
| VerfasserIn |
P. B. Holden, N. R. Edwards, S. A. Müller, K. I. C. Oliver, R. M. Death, A. Ridgwell |
| 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. 3 ; Nr. 10, no. 3 (2013-03-19), S.1815-1833 |
| Datensatznummer |
250018157
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| Publikation (Nr.) |
 copernicus.org/bg-10-1815-2013.pdf |
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| Zusammenfassung |
| We describe the design and evaluation of a large ensemble of coupled
climate–carbon cycle simulations with the Earth system model of intermediate
complexity GENIE. This ensemble has been designed for application to a range
of carbon cycle questions, including the causes of late-Quaternary
fluctuations in atmospheric CO2. Here we evaluate the ensemble by
applying it to a transient experiment over the recent industrial era (1858 to
2008 AD). We employ singular vector decomposition and principal component
emulation to investigate the spatial modes of ensemble variability of oceanic
dissolved inorganic carbon (DIC) δ13C, considering both the spun-up
pre-industrial state and the transient change. These analyses allow us to
separate the natural (pre-industrial) and anthropogenic controls on the
δ13CDIC distribution. We apply the same
dimensionally-reduced emulation techniques to consider the drivers of the
spatial uncertainty in anthropogenic DIC. We show that the sources of
uncertainty related to the uptake of anthropogenic
δ13CDIC and DIC are quite distinct. Uncertainty in
anthropogenic δ13C uptake is controlled by air–sea gas exchange,
which explains 63% of modelled variance. This mode of variability is
largely absent from the ensemble variability in CO2 uptake, which is
rather driven by uncertainties in thermocline ventilation rates. Although the
need to account for air–sea gas exchange is well known, these results
suggest that, to leading order, uncertainties in the ocean uptake of
anthropogenic 13C and CO2 are governed by very different processes.
This illustrates the difficulties in reconstructing one from the other, and
furthermore highlights the need for careful targeting of both
δ13CDIC and DIC observations to better constrain the
ocean sink of anthropogenic CO2. |
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