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| Titel |
Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America |
| VerfasserIn |
P. Castellanos, K. F. Boersma, G. R. van der Werf |
| 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 ; 14, no. 8 ; Nr. 14, no. 8 (2014-04-17), S.3929-3943 |
| Datensatznummer |
250118626
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| Publikation (Nr.) |
 copernicus.org/acp-14-3929-2014.pdf |
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| Zusammenfassung |
| Biomass burning is an important contributor to global total emissions of
NOx (NO+NO2). Generally bottom-up fire emissions models
calculate NOx emissions by multiplying fuel consumption estimates with
static biome-specific emission factors, defined in units of grams of NO per
kilogram of dry matter consumed. Emission factors are a significant source
of uncertainty in bottom-up fire emissions modeling because relatively few
observations are available to characterize the large spatial and temporal
variability of burning conditions. In this paper we use NO2
tropospheric column observations from the Ozone Monitoring Instrument (OMI)
from the year 2005 over South America to calculate monthly NOx emission
factors for four fire types: deforestation, savanna/grassland, woodland, and
agricultural waste burning. In general, the spatial patterns in NOx
emission factors calculated in this work are consistent with emission
factors derived from in situ measurements from the region but are more
variable than published biome-specific global average emission factors
widely used in bottom-up fire emissions inventories such as the Global Fire
Emissions Database (GFED). Satellite-based NOx emission factors also
indicate substantial temporal variability in burning conditions. Overall, we
found that deforestation fires have the lowest NOx emission factors, on
average 30% lower than the emission factors used in GFED v3. Agricultural
fire NOx emission factors were the highest, on average a factor of 1.8
higher than GFED v3 values. For savanna, woodland, and deforestation fires,
early dry season NOx emission factors were a factor of ~1.5–2
higher than late dry season emission factors. A minimum in the
NOx emission factor seasonal cycle for deforestation fires occurred in
August, the time period of severe drought in South America in 2005,
supporting the hypothesis that prolonged dry spells may lead to an increase
in the contribution of smoldering combustion from large-diameter fuels,
offsetting the higher combustion efficiency of dryer fine fuels. We
evaluated the OMI-derived NOx emission factors with SCIAMACHY NO2
tropospheric column observations and found improved model performance in
regions dominated by fire emissions. |
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