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| Titel |
GCM characteristics explain the majority of uncertainty in projected 21st century terrestrial ecosystem carbon balance |
| VerfasserIn |
A. Ahlstrom, B. Smith, J. Lindström, M. Rummukainen, C. B. Uvo |
| 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 (2013-03-07), S.1517-1528 |
| Datensatznummer |
250018139
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| Publikation (Nr.) |
 copernicus.org/bg-10-1517-2013.pdf |
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| Zusammenfassung |
| One of the largest sources of uncertainties in modelling of the future
global climate is the response of the terrestrial carbon cycle. Studies have
shown that it is likely that the extant land sink of carbon will weaken in a
warming climate. Should this happen, a larger portion of the annual carbon
dioxide emissions will remain in the atmosphere, and further increase global
warming, which in turn may further weaken the land sink. We investigate the
potential sensitivity of global terrestrial ecosystem carbon balance to
differences in future climate simulated by four general circulation models
(GCMs) under three different CO2 concentration scenarios. We find that
the response in simulated carbon balance is more influenced by GCMs than
CO2 concentration scenarios. Empirical orthogonal function (EOF)
analysis of sea surface temperatures (SSTs) reveals differences among GCMs
in simulated SST variability leading to decreased tropical ecosystem
productivity in two out of four GCMs. We extract parameters describing GCM
characteristics by parameterizing a statistical emulator mimicking the
carbon balance response simulated by a full dynamic ecosystem model. By
sampling two GCM-specific parameters and global temperatures we create 60
new "artificial" GCMs and investigate the extent to which the GCM
characteristics may explain the uncertainty in global carbon balance under
future radiative forcing. Differences among GCMs in the representation of
SST variability and ENSO and its effect on precipitation and temperature
patterns explain the majority of the uncertainty in the future evolution of
global terrestrial ecosystem carbon in our analysis. We suggest that the
characterisation and evaluation of patterns and trends in simulated SST
variability should be a priority for the further development of GCMs, in
particular as vegetation dynamics and carbon cycle feedbacks are
incorporated. |
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