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| Titel |
Representing northern peatland microtopography and hydrology within the Community Land Model |
| VerfasserIn |
X. Shi, P. E. Thornton, D. M. Ricciuto, P. J. Hanson, J. Mao, S. D. Sebestyen, N. A. Griffiths, G. Bisht |
| 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 ; 12, no. 21 ; Nr. 12, no. 21 (2015-11-12), S.6463-6477 |
| Datensatznummer |
250118162
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| Publikation (Nr.) |
 copernicus.org/bg-12-6463-2015.pdf |
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| Zusammenfassung |
| Predictive understanding of northern peatland hydrology is a necessary
precursor to understanding the fate of massive carbon stores in these
systems under the influence of present and future climate change. Current
models have begun to address microtopographic controls on peatland
hydrology, but none have included a prognostic calculation of peatland water
table depth for a vegetated wetland, independent of prescribed regional
water tables. We introduce here a new configuration of the Community Land
Model (CLM) which includes a fully prognostic water table calculation for a
vegetated peatland. Our structural and process changes to CLM focus on
modifications needed to represent the hydrologic cycle of bogs environment
with perched water tables, as well as distinct hydrologic dynamics and
vegetation communities of the raised hummock and sunken hollow
microtopography characteristic of peatland bogs. The modified model was
parameterized and independently evaluated against observations from an
ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for
the Spruce and Peatland Responses Under Climatic and Environmental Change
experiment (SPRUCE). Simulated water table levels compared well with
site-level observations. The new model predicts hydrologic changes in
response to planned warming at the SPRUCE site. At present, standing water
is commonly observed in bog hollows after large rainfall events during the
growing season, but simulations suggest a sharp decrease in water table
levels due to increased evapotranspiration under the most extreme warming
level, nearly eliminating the occurrence of standing water in the growing
season. Simulated soil energy balance was strongly influenced by reduced
winter snowpack under warming simulations, with the warming influence on
soil temperature partly offset by the loss of insulating snowpack in early
and late winter. The new model provides improved predictive capacity for
seasonal hydrological dynamics in northern peatlands, and provides a useful
foundation for investigation of northern peatland carbon exchange. |
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