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| Titel |
The sensitivity of carbon turnover in the Community Land Model to modified assumptions about soil processes |
| VerfasserIn |
B. Foereid, D. S. Ward, N. Mahowald, E. Paterson, Joh. Lehmann |
| 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. 1 ; Nr. 5, no. 1 (2014-06-02), S.211-221 |
| Datensatznummer |
250115302
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| Publikation (Nr.) |
 copernicus.org/esd-5-211-2014.pdf |
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| Zusammenfassung |
| Soil organic matter (SOM) is the largest store of organic carbon (C) in the
biosphere, but the turnover of SOM is still incompletely understood and not
well described in global C cycle models. Here we use the Community Land
Model (CLM) and compare the output for soil organic C stocks (SOC) to
estimates from a global data set. We also modify the assumptions about SOC
turnover in two ways: (1) we assume distinct temperature sensitivities of SOC
pools with different turnover time and (2) we assume a priming effect, such
that the decomposition rate of native SOC increases in response to a supply
of fresh organic matter. The standard model predicted the global
distribution of SOC reasonably well in most areas, but it failed to predict
the very high stocks of SOC at high latitudes. It also predicted too much
SOC in areas with high plant productivity, such as tropical rainforests and
some midlatitude areas. Total SOC at equilibrium was reduced by a small amount
(<1% globally) when we assume that the temperature sensitivity of SOC
decomposition is dependent on the turnover rate of the component pools.
Including a priming effect reduced total global SOC more (6.6%
globally) and led to decreased SOC in areas with high plant input (tropical
and temperate forests), which were also the areas where the unmodified model
overpredicted SOC (by about 40%). The model was then run with climate
change prediction until 2100 for the standard and modified versions. Future
simulations showed that differences between the standard and modified
versions were maintained in a future with climate change (4–6 and 23–47 Pg
difference in soil carbon between standard simulation and the modified
simulation with temperature sensitivity and priming respectively). Although the
relative changes are small, they are likely to be larger in a fully coupled
simulation, and thus warrant future work. |
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