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| Titel |
Improving the representation of fire disturbance in dynamic vegetation models by assimilating satellite data: a case study over the Arctic |
| VerfasserIn |
E. P. Kantzas, S. Quegan, M. Lomas |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 8, no. 8 ; Nr. 8, no. 8 (2015-08-21), S.2597-2609 |
| Datensatznummer |
250116508
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| Publikation (Nr.) |
 copernicus.org/gmd-8-2597-2015.pdf |
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| Zusammenfassung |
| Fire provides an impulsive and stochastic pathway for carbon from the
terrestrial biosphere to enter the atmosphere. Despite fire emissions being
of similar magnitude to net ecosystem exchange in many biomes, even the most
complex dynamic vegetation models (DVMs) embedded in general circulation
models contain poor representations of fire behaviour and dynamics, such as
propagation and distribution of fire sizes. A model-independent methodology
is developed which addresses this issue. Its focus is on the Arctic where
fire is linked to permafrost dynamics and on occasion can release great
amounts of carbon from carbon-rich organic soils. Connected-component
labelling is used to identify individual fire events across Canada and Russia
from daily, low-resolution burned area satellite products, and the obtained
fire size probability distributions are validated against historical data.
This allows the creation of a fire database holding information on area
burned and temporal evolution of fires in space and time. A method of
assimilating the statistical distribution of fire area into a DVM whilst
maintaining its fire return interval is then described. The algorithm imposes
a regional scale spatially dependent fire regime on a sub-scale spatially
independent model; the fire regime is described by large-scale statistical
distributions of fire intensity and spatial extent, and the temporal dynamics
(fire return intervals) are determined locally. This permits DVMs to estimate
many aspects of post-fire dynamics that cannot occur under their current
representations of fire, as is illustrated by considering the modelled
evolution of land cover, biomass and net ecosystem exchange after a fire. |
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