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| Titel |
Wildfire particulate matter in Europe during summer 2003: meso-scale modeling of smoke emissions, transport and radiative effects |
| VerfasserIn |
A. Hodzic, S. Madronich, B. Bohn, S. Massie, L. Menut, C. Wiedinmyer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 7, no. 15 ; Nr. 7, no. 15 (2007-08-02), S.4043-4064 |
| Datensatznummer |
250005151
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| Publikation (Nr.) |
 copernicus.org/acp-7-4043-2007.pdf |
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| Zusammenfassung |
| The present study investigates effects of wildfire emissions on air quality
in Europe during an intense fire season that occurred in summer 2003. A
meso-scale chemistry transport model CHIMERE is used, together with ground
based and satellite aerosol optical measurements, to assess the dispersion
of fire emissions and to quantify the associated radiative effects. The
model has been improved to take into account a MODIS-derived daily smoke
emission inventory as well as the injection altitude of smoke particles. The
simulated aerosol optical properties are put into a radiative transfer model
to estimate (off-line) the effects of smoke particles on photolysis rates
and atmospheric radiative forcing. We have found that the simulated
wildfires generated comparable amounts of primary aerosol pollutants (130 kTons of PM2.5, fine particles)
to anthropogenic sources during August
2003, and caused significant changes in aerosol optical properties not only
close to the fire source regions, but also over a large part of Europe as a
result of the long-range transport of the smoke. Including these emissions
into the model significantly improved its performance in simulating observed
aerosol concentrations and optical properties. Quantitative comparison with
MODIS and POLDER data during the major fire event (3–8 August 2003) showed
the ability of the model to reproduce high aerosol optical thickness (AOT)
over Northern Europe caused by the advection of the smoke plume from the
Portugal source region. Although there was a fairly good spatial agreement
with satellite data (correlation coefficients ranging from 0.4 to 0.9), the
temporal variability of AOT data at specific AERONET locations was not well
captured by the model. Statistical analyses of model-simulated AOT data at
AERONET ground stations showed a significant decrease in the model biases
suggesting that wildfire emissions are responsible for a 30% enhancement
in mean AOT values during the heat-wave episode. The implications for air
quality over a large part of Europe are significant during this episode.
First, directly, the modeled wildfire emissions caused an increase in
average PM2.5 ground concentrations from 20 to 200%. The largest
enhancement in PM2.5 concentrations stayed, however, confined within a
200 km area around the fire source locations and reached up to 40 μg/m³.
Second, indirectly, the presence of elevated smoke layers over
Europe significantly altered atmospheric radiative properties: the model
results imply a 10 to 30% decrease in photolysis rates and an increase in
atmospheric radiative forcing of 10–35 W m−2 during the period of
strong fire influence throughout a large part of Europe. These results
suggest that sporadic wildfire events may have significant effects on
regional photochemistry and atmospheric stability, and need to be considered
in current chemistry-transport models. |
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