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| Titel |
Modelling carbon cycle in boreal wetlands with the Earth System Model ECHAM6/MPIOM |
| VerfasserIn |
Robert J. Getzieh, Victor Brovkin, Thomas Kleinen, Maarit Raivonen, Sanna Sevanto |
| 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 |
250041410
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| Zusammenfassung |
| Â Â Â Â Â Wetlands of the northern high latitudes provide excellent conditions for peat
accumulation and methanogenesis. High moisture and low O2 content in the soils lead to
effective preservation of soil organic matter and methane emissions. Boreal Wetlands contain
about 450 PgC and currently constitute a significant natural source of methane (CH4) even
though they cover only 3% of the global land surface.
     While storing carbon and removing CO2 from the atmosphere, boreal wetlands
have contributed to global cooling on millennial timescales. Undisturbed boreal wetlands are
likely to continue functioning as a net carbon sink. On the other hand these carbon pools
might be destabilised in future since they are sensitive to climate change. Given that
processes of peat accumulation and decay are closely dependent on hydrology and
temperature, this balance may be altered significantly in the future. As a result, northern
wetlands could have a large impact on carbon cycle-climate feedback mechanisms and
therefore play an important role in global carbon cycle dynamics. However global
biogeochemistry models used for simulations of CO2 dynamics in past and future climates
usually neglect carbon cycle in wetlands.
     We investigate the potential for positive or negative feedbacks to the climate system
through fluxes of greenhouse gases (CO2 and CH4) with the general circulation model
ECHAM6/MPIOM. A generic model of peat accumulation and decay has been
developed and implemented into the land surface module JSBACH. We consider
anaerobic biogeochemical processes which lead to formation of thick organic soils.
Furthermore we consider specific wetland plant functional types (PFTs) in our model
such as vascular plants (sedges) which impact methane transport and oxidation
processes and non vascular plants (sphagnum mosses) which are promoting peat
growth.
     As prototypes we use the modelling approaches by Frolking et al. (2001) as well as
Walter & Heimann (2001) for the peat dynamics, and the wetland model by Wania (2008) for
vegetation cover and methane emissions. An initial distribution of wetlands follows the
GLWD-3 map by Lehner and Döll (2004). A dynamical wetlands hydrology scheme (T.
Stacke) and a methane transport and emission model (M. Raivonen) are at the moment also
under development at the MPI for Meteorology respectively in close cooperation
with the University of Helsinki. First results of our modelling approach will be
presented.
REFERENCES
S. Frolking et al., Ecosystems 4, 479-498 (2001).
B. Lehner et al., Journal of Hydrology 296, 1-22 (2004).
B. P. Walter et al., J. Geophys. Res. 106, D24, 34189-34206 and 34207-34219 (2001).
R. Wania et al., Global Biogeochem. Cycles 23, GB3014 and GB3015 (2009). |
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