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| Titel |
Global satellite analysis of the relation between aerosols and short-lived trace gases |
| VerfasserIn |
J. P. Veefkind, K. F. Boersma, J. Wang, T. P. Kurosu, N. Krotkov, K. Chance, P. F. Levelt |
| 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 ; 11, no. 3 ; Nr. 11, no. 3 (2011-02-14), S.1255-1267 |
| Datensatznummer |
250009306
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| Publikation (Nr.) |
 copernicus.org/acp-11-1255-2011.pdf |
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| Zusammenfassung |
| The spatial and temporal correlations between concurrent satellite
observations of aerosol optical thickness (AOT) from the Moderate Resolution
Imaging Spectroradiometer (MODIS) and tropospheric columns of nitrogen
dioxide (NO2), sulfur dioxide (SO2), and formaldehyde (HCHO) from the Ozone Monitoring
Instrument (OMI) are used to infer information on the global composition of
aerosol particles. When averaging the satellite data over large regions and
longer time periods, we find significant correlation between MODIS AOT and
OMI trace gas columns for various regions in the world. This shows that
these enhanced aerosol and trace gas concentrations originate from common sources,
such as fossil fuel combustion, biomass burning, and organic compounds
released from the biosphere. This leads us to propose that
satellite-inferred AOT to NO2 ratios for regions with comparable
photochemical regimes can be used as indicators for the relative regional
pollution control of combustion processes. Indeed, satellites observe low AOT to
NO2 ratios over the eastern United States and western Europe, and high
AOT to NO2 ratios over comparably industrialized regions in eastern
Europe and China. Emission databases and OMI SO2 observations over
these regions suggest a much stronger sulfur contribution to aerosol
formation than over the well-regulated areas of the eastern United States
and western Europe. Furthermore, satellite observations show AOT to NO2
ratios are a factor 100 higher over biomass burning regions than over
industrialized areas, reflecting the unregulated burning practices with
strong primary particle emissions in the tropics compared to the heavily
controlled combustion processes in the industrialized Northern Hemisphere.
Simulations with a global chemistry transport model (GEOS-Chem) capture most
of these variations, although on regional scales significant differences are found.
Wintertime aerosol concentrations show strongest correlations with NO2 throughout most of
the Northern Hemisphere. During summertime, AOT is often (also) correlated
with enhanced HCHO concentrations, reflecting the importance of secondary
organic aerosol formation in that season. We also find significant
correlations between AOT and HCHO over biomass burning regions, the tropics
in general, and over industrialized regions in southeastern Asia. The
distinct summertime maximum in AOT (0.4 at 550 nm) and HCHO over the
southeastern United States strengthens existing hypotheses that local
emissions of volatile organic compounds lead to the formation of secondary
organic aerosols there. GEOS-Chem underestimates the AOT over the
southeastern United States by a factor of 2, most likely due to too strong
precipitation and too low SOA yield in the model. |
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