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| Titel |
Quantifying the effect of lichen and bryophyte cover on permafrost soil within a global land surface model |
| VerfasserIn |
Philipp Porada, Altug Ekici, Christian Beer |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250133717
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| Publikation (Nr.) |
 EGU/EGU2016-14360.pdf |
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| Zusammenfassung |
| Vegetation near the surface, such as bryophytes and lichens, has an insulating effect on the
soil at high latitudes and it can therefore protect permafrost conditions. Warming due to
climate change, however, may change the average surface coverage of bryophytes and
lichens. This can result in permafrost thawing associated with a release of soil carbon to the
atmosphere, which may lead to a positive feedback on atmospheric CO2. Thus, it
is important to predict how the bryophyte and lichen cover at high latitudes will
react to environmental change. However, current global land surface models so far
contain mostly empirical approaches to represent bryophytes and lichens, which
makes it impractical to predict their future state and function. For this reason, we
integrate a process-based model of bryophyte and lichen growth into the global land
surface model JSBACH. We explicitly represent dynamic thermal properties of the
bryophyte and lichen cover and their relation to climate. Subsequently, we compare
simulations with and without bryophyte and lichen cover to quantify the insulating
effect.
We estimate an annual average cooling effect of the bryophyte and lichen cover of 2.7 K
on topsoil temperature for the northern high latitudes under current climate. Locally, the
cooling may reach up to 5.7 K. Moreover, we show that neglecting dynamic properties of the
bryophyte and lichen cover by using a simple, empirical scheme only results in an average
cooling of around 0.5 K. This suggests that bryophytes and lichens have a significant impact
on soil temperature in high-latitude ecosystems and also that a process-based description of
their thermal properties is necessary for a realistic representation of the cooling effect. |
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