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| Titel |
Influences of temporal fuel variability on modelling fire occurrence and emissions |
| VerfasserIn |
Gitta Lasslop, Silvia Kloster |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250092437
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| Publikation (Nr.) |
 EGU/EGU2014-6782.pdf |
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| Zusammenfassung |
| Fires are a global phenomenon with diverse influences on vegetation distribution,
biogeochemical cycles and physical properties of the Earth surface. Fires can occur given the
availability of fuel, which needs to be sufficiently dry, and the presence of an ignition source.
To estimate global carbon emissions from fires different methods are used to assess the
availability and amount of fuel. There are static approaches based on the land cover
type combined with a vegetation type dependent biomass density and dynamic
approaches based on vegetation models. Static approaches cannot account for the
seasonal or long term variation in fuels and can therefore not represent a temporal
occurrence of fuel limitation or long term changes as they can be expected from CO2
fertilization.
In this study we want to address the influence of seasonal fuel variability and the variability
caused by changes in CO2 concentration from preindustrial to 2005. We use a land surface
model (JSBACH) including an implementation of the mechanistic fire model SPITFIRE. We
perform a reference simulation with daily updated fuel load and simulations with the fuel
load fixed to the mean fuel load, to maximum monthly fuel load and the minimum
monthly fuel load of the reference. To study the influence of CO2 fertilization on fire
occurrence and emissions we compare a simulation with historical CO2 increase and
historical climate, with a simulation where we use constant preindustrial CO2 for
photosythesis.
The simulation using the mean fuel load shows similar results to the reference run.
The simulations using minimum and maximum fuel show a large difference in
global values (311 and 416 Mha burned globally, 2.25 and 2.67 Pg C emissions,
respectively), but similar global distributions. Differences occur mainly in fuel
limited regions. When establishing biomass density maps the seasonality should be
considered, as the deviations between minimum and maximum fuel load within a year
show a strong impact on the global sum. The influence on the seasonality differs
between regions. The simulation with preindustrial CO2 fertilization shows a reduction
not only in carbon emissions but also in burned area compared to the historical
simulation.
We conclude, that static approaches may perform reasonably for annual estimates under
present day climate, but may show biases for projections to past or future when not
considering the effect of CO2 on the vegetation carbon pools. |
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