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| Titel |
Global atmospheric carbon budget: results from an ensemble of atmospheric CO2 inversions |
| VerfasserIn |
P. Peylin, R. M. Law, K. R. Gurney, F. Chevallier, A. R. Jacobson, T. Maki, Y. Niwa, P. K. Patra, W. Peters, P. J. Rayner, C. Rödenbeck, I. T. Laan-Luijkx, X. Zhang |
| 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. 10 ; Nr. 10, no. 10 (2013-10-24), S.6699-6720 |
| Datensatznummer |
250085376
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| Publikation (Nr.) |
 copernicus.org/bg-10-6699-2013.pdf |
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| Zusammenfassung |
| Atmospheric CO2 inversions estimate surface carbon fluxes from an
optimal fit to atmospheric CO2 measurements, usually including prior
constraints on the flux estimates. Eleven sets of carbon flux estimates are
compared, generated by different inversions systems that vary in their
inversions methods, choice of atmospheric data, transport model and prior
information. The inversions were run for at least 5 yr in the period between
1990 and 2010. Mean fluxes for 2001–2004, seasonal cycles, interannual
variability and trends are compared for the tropics and northern and southern
extra-tropics, and separately for land and ocean. Some
continental/basin-scale subdivisions are also considered where the
atmospheric network is denser. Four-year mean fluxes are reasonably
consistent across inversions at global/latitudinal scale, with a large total
(land plus ocean) carbon uptake in the north (−3.4 Pg C yr−1
(±0.5 Pg C yr−1 standard deviation), with slightly more uptake
over land than over ocean), a significant although more variable source over
the tropics (1.6 ± 0.9 Pg C yr−1) and a compensatory sink of
similar magnitude in the south (−1.4 ± 0.5 Pg C yr−1)
corresponding mainly to an ocean sink. Largest differences across inversions
occur in the balance between tropical land sources and southern land sinks.
Interannual variability (IAV) in carbon fluxes is larger for land than ocean
regions (standard deviation around 1.06 versus 0.33 Pg C yr−1 for the
1996–2007 period), with much higher consistency among the inversions
for the land. While the tropical land explains most of the IAV (standard
deviation ~ 0.65 Pg C yr−1), the northern and southern land
also contribute (standard deviation ~ 0.39 Pg C yr−1). Most
inversions tend to indicate an increase of the northern land carbon uptake
from late 1990s to 2008 (around 0.1 Pg C yr−1, predominantly in
North Asia. The mean seasonal cycle appears to be well constrained by the
atmospheric data over the northern land (at the continental scale), but still
highly dependent on the prior flux seasonality over the ocean. Finally we
provide recommendations to interpret the regional fluxes, along with the
uncertainty estimates. |
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