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| Titel |
Soil carbon model Yasso07 in a global Earth system model |
| VerfasserIn |
T. Thum, S. Sevanto, P. Räisänen, T. Aalto, T. Bergman, V. Brovkin, H. Järvinen, T. Laurila, J. Liski, T. Raddatz |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026493
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| Zusammenfassung |
| The largest terrestrial carbon storage is located in the soil. Climate change might accelerate
decomposition processes in the soil and thus release large amounts of carbon from the soil to
the atmosphere via heterotrophic respiration. Interactions between heterotrophic
respiration and climate are complicated and might include significant feedback effects.
To assess what will happen to soil carbon stocks, coupled climate-carbon cycle
models need to be up to date presenting our current knowledge of decomposition
processes in the soil. Yasso07 is a new soil carbon model parameterized with a
large experimental data set including litter decomposition data with wide global
coverage.
Within the activities of the COSMOS Earth system modelling network (cosmos.enes.org),
the atmosphere/terrestrial biosphere model ECHAM5/JSBACH (www.mpimet.mpg.de) is
employed. We replaced the soil carbon decomposition submodel of the JSBACH with the
Yasso07 submodel and compared its performance with the original formulation. The original
model consists of a fast and a slow carbon pool. In Yasso07 the incoming litter is divided into
four carbon pools according to the chemical composition of litter that depends on plant
functional type; in addition, there are pools for woody litter and humus. We studied
how these two soil models simulate soil carbon storage in equilibrium to today’s
climate. Yasso07 stored less carbon in the soil and had different dynamical responses
to climate variations than the original version. For example, Yasso07 was more
sensitive to drought. We also compared the model results to measured CO2 fluxes
from eddy covariance sites as well as CO2mixing ratio measurements. At Pallas
site in northern Finland the amplitude of the annual variation of CO2 mixing ratio
was closer to the measurements in the original model, but the timing of the annual
cycle was better simulated by Yasso07. Our next step is to study how these two soil
models will respond to different climate scenarios in a fully coupled climate model. |
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