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| Titel |
Estimating Asian terrestrial carbon fluxes from CONTRAIL aircraft and surface CO2 observations for the period 2006-2010 |
| VerfasserIn |
H. F. Zhang, B. Z. Chen, I. T. van der Laan-Luijk, T. Machida, H. Matsueda, Y. Sawa, Y. Fukuyama, R. Langenfelds, M. van der Schoot, G. Xu, J. W. Yan, M. L. Cheng, L. X. Zhou, P. P. Tans, W. Peters |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 11 ; Nr. 14, no. 11 (2014-06-11), S.5807-5824 |
| Datensatznummer |
250118788
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| Publikation (Nr.) |
 copernicus.org/acp-14-5807-2014.pdf |
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| Zusammenfassung |
| Current estimates of the terrestrial carbon fluxes in Asia show large
uncertainties particularly in the boreal and mid-latitudes and in China. In
this paper, we present an updated carbon flux estimate for Asia ("Asia"
refers to lands as far west as the Urals and is divided into boreal Eurasia,
temperate Eurasia and tropical Asia based on TransCom regions) by introducing
aircraft CO2 measurements from the CONTRAIL (Comprehensive Observation
Network for Trace gases by Airline) program into an inversion modeling system
based on the CarbonTracker framework. We estimated the averaged annual total
Asian terrestrial land CO2 sink was about −1.56 Pg C yr−1 over
the period 2006–2010, which offsets about one-third of the fossil fuel
emission from Asia (+4.15 Pg C yr−1). The uncertainty of the
terrestrial uptake estimate was derived from a set of sensitivity tests and
ranged from −1.07 to −1.80 Pg C yr−1, comparable to the formal
Gaussian error of ±1.18 Pg C yr−1 (1-sigma). The largest sink was
found in forests, predominantly in coniferous forests
(−0.64 ± 0.70 Pg C yr−1) and mixed forests
(−0.14 ± 0.27 Pg C yr−1); and the second and third large
carbon sinks were found in grass/shrub lands and croplands, accounting for
−0.44 ± 0.48 Pg C yr−1 and
−0.20 ± 0.48 Pg C yr−1, respectively. The carbon fluxes per
ecosystem type have large a priori Gaussian uncertainties, and the reduction
of uncertainty based on assimilation of sparse observations over Asia is
modest (8.7–25.5%) for most individual ecosystems. The ecosystem flux
adjustments follow the detailed a priori spatial patterns by design, which
further increases the reliance on the a priori biosphere exchange model. The
peak-to-peak amplitude of inter-annual variability (IAV) was
0.57 Pg C yr−1 ranging from −1.71 Pg C yr−1 to
−2.28 Pg C yr−1. The IAV analysis reveals that the Asian CO2
sink was sensitive to climate variations, with the lowest uptake in 2010
concurrent with a summer flood and autumn drought and the largest CO2
sink in 2009 owing to favorable temperature and plentiful precipitation
conditions. We also found the inclusion of the CONTRAIL data in the inversion
modeling system reduced the uncertainty by 11% over the whole Asian
region, with a large reduction in the southeast of boreal Eurasia, southeast
of temperate Eurasia and most tropical Asian areas. |
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