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| Titel |
The role of peatlands in interglacial Carbon cycle dynamics - a modelling perspective |
| VerfasserIn |
Thomas Kleinen, Victor Brovkin |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250041834
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| Zusammenfassung |
| Arctic and Boreal peatlands cover about 3% of the Earth’s land surface area only, but they
contain substantial amounts of carbon. Estimates of peat accumulated during the Holocene
reach up to 450 GtC. On longer timescales the carbon uptake by peatlands therefore becomes
a cumulative flux of substantial magnitude, though it is rather small if one considers the short
timescales only. We will present results showing the influence of the carbon uptake by
peatlands on Holocene CO2 concentrations.
Using the coupled climate carbon cycle model CLIMBER2-LPJ we are considering all
natural factors influencing the atmospheric CO2 concentration, including carbon uptake by
peatlands. CLIMBER2 is a climate model of intermediate complexity, containing a dynamic
atmosphere and ocean, as well as sea ice and land surface modules. Its coarse spatial
resolution leads to a high computational efficiency, which allows long-term transient
integrations of the coupled model. Land carbon dynamics are computed using the dynamic
global vegetation model LPJ. LPJ is run at a high spatial resolution of 0.5° and coupled to
CLIMBER2 using the climate anomalies approach. Changes in land carbon storage as a
response to changes in climate or atmospheric CO2 are therefore taken into account
interactively at high spatial resolution.
While it is easily possible to consider the influence of peat formation on the carbon
cycle during the Holocene by using external scenarios of peat accumulation, this
approach is not viable for previous interglacials. Most peat deposits accumulated during
previous interglacials were removed in the course of glaciation, and we therefore
have no estimates to base external scenarios on. In order to consider this forcing in
models, it is therefore necessary to incorporate peat formation into global models
dynamically.
Integrating peatland dynamics into dynamic global vegetation models is a non-trivial
problem due to the coarse representation of the land surface. Since wetland and
therefore peatland size often is substantially smaller than the model grid cells, the
dynamic representation of wetland extent can only be accomplished by incorporating
sub-gridcell information on hydrological properties of the land surface. We will
present the approach we have taken for integrating peat dynamics into the DGVM
LPJ, consisting of a scheme for the dynamical determination of wetland extent
based on high resolution topographical data, and the carbon dynamics occurring in
peatlands.
We will finish the presentation by showing model results for peat dynamics during the
previous interglacial, the Eemian. |
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