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| Titel |
Continued increase in atmospheric CO2 seasonal amplitude in the 21st century projected by the CMIP5 Earth system models |
| VerfasserIn |
F. Zhao, N. Zeng |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 5, no. 2 ; Nr. 5, no. 2 (2014-12-01), S.423-439 |
| Datensatznummer |
250115375
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| Publikation (Nr.) |
 copernicus.org/esd-5-423-2014.pdf |
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| Zusammenfassung |
| In the Northern Hemisphere, atmospheric CO2 concentration declines in
spring and summer, and rises in fall and winter. Ground-based and
aircraft-based observation records indicate that the amplitude of this
seasonal cycle has increased in the past. Will this trend continue in the
future? In this paper, we analyzed simulations for historical (1850–2005)
and future (RCP8.5, 2006–2100) periods produced by 10 Earth system models
participating in the fifth phase of the Coupled Model Intercomparison
Project (CMIP5). Our results present a model consensus that the increase of
CO2 seasonal amplitude continues throughout the 21st century.
Multi-model ensemble relative amplitude of detrended global mean CO2
seasonal cycle increases by 62 ± 19% in 2081–2090, compared to
1961–1970. This amplitude increase corresponds to a 68 ± 25%
increase in net biosphere production (NBP). The results show that the
increase of NBP amplitude mainly comes from enhanced ecosystem uptake during
Northern Hemisphere growing season under future CO2 and temperature
conditions. Separate analyses on net primary production (NPP) and
respiration reveal that enhanced ecosystem carbon uptake contributes about
75% of the amplitude increase. Stimulated by higher CO2
concentration and high-latitude warming, enhanced NPP likely outcompetes
increased respiration at higher temperature, resulting in a higher net
uptake during the northern growing season. The zonal distribution and
spatial pattern of NBP change suggest that regions north of 45° N
dominate the amplitude increase. Models that simulate a stronger carbon
uptake also tend to show a larger increase of NBP seasonal amplitude, and
the cross-model correlation is significant (R=0.73, p< 0.05). |
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