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| Titel |
The empirical relationship between satellite-derived tropospheric NO2 and fire radiative power and possible implications for fire emission rates of NOx |
| VerfasserIn |
S. F. Schreier, A. Richter, J. W. Kaiser, J. P. Burrows |
| 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. 5 ; Nr. 14, no. 5 (2014-03-10), S.2447-2466 |
| Datensatznummer |
250118470
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| Publikation (Nr.) |
 copernicus.org/acp-14-2447-2014.pdf |
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| Zusammenfassung |
| Nitrogen oxides (NOx) play key roles in atmospheric chemistry,
air pollution, and climate. While the largest fraction of these reactive
gases is released by anthropogenic emission sources, a significant amount can
be attributed to vegetation fires. In this study, NO2 from GOME-2 on
board EUMETSAT's MetOp-A and OMI on board NASA's Aura as well as fire
radiative power (FRP) from the measurements of MODIS on board NASA's Terra
and Aqua satellites are used to derive fire emission rates (FERs) of
NOx for different types of vegetation using a simple statistical
approach. Monthly means of tropospheric NO2 vertical columns (TVC
NO2) have been analyzed for their temporal correlation with the monthly
means of FRP for five consecutive years from 2007 to 2011 on a horizontal
1° × 1° grid. The strongest correlation is found to
be largely confined to tropical and subtropical regions, which account for
more than 80% of yearly burned area, on average, globally. In these
regions, the seasonal variation of fire intensity, expressed by the FRP data,
is similar to the pattern of TVC NO2. As chemical models typically
require values for the amount of NOx being released as a function
of time, we have converted the retrieved TVC NO2 into production rates
of NOx from fire (Pf) by assuming a constant lifetime
of NOx. The comparison between Pf and NOx
emissions from the Global Fire Emissions Database (GFEDv3.1) over 5
characteristic biomass burning regions in the tropics and subtropics shows
good agreement. By separating the monthly means of Pf and FRP
according to land cover type, FERs of NOx could be derived for
different biomes. The estimated FERs for the dominating types of vegetation
burned are lowest for open shrublands and savannas (0.28–1.03 g
NOx s−1 MW−1) and highest for croplands and woody
savannas (0.82–1.56 g NOx s−1 MW−1). This analysis
demonstrates that the strong empirical relationship between TVC NO2 and
FRP and the following simplified assumptions are a useful tool for the
characterization of NOx emission rates from vegetation fires in
the tropics and subtropics. Possible factors affecting the magnitude of the
obtained values are discussed. |
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