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| Titel |
Attribution of modeled atmospheric sulfate and SO2 in the Northern Hemisphere for June-July 1997 |
| VerfasserIn |
C. M. Benkovitz, S. E. Schwartz, M. P. Jensen, M. A. Miller |
| 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 ; 6, no. 12 ; Nr. 6, no. 12 (2006-10-23), S.4723-4738 |
| Datensatznummer |
250004149
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| Publikation (Nr.) |
 copernicus.org/acp-6-4723-2006.pdf |
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| Zusammenfassung |
| Anthropogenic sulfate aerosol is a major contributor to shortwave radiative
forcing of climate change by direct light scattering and by perturbing cloud
properties and to local concentrations of atmospheric particulate matter.
Here we analyze results from previously published calculations with an
Eulerian transport model for atmospheric sulfur species in the Northern
Hemisphere in June–July, 1997 to quantify the absolute and relative
contributions of specific source regions (North America, Europe, and Asia)
and SO2-to-sulfate conversion mechanisms (gas-phase, aqueous-phase and
primary sulfate) to sulfate and SO2 column burdens as a function of
location and time. Although material emitted within a given region dominates
the sulfate and SO2 column burden in that region, examination of time
series at specific locations shows that material imported from outside can
make a substantial and occasionally dominant contribution. Frequently the
major fraction of these exogenous contributions to the sulfate column burden
was present aloft, thus minimally impacting air quality at the surface, but
contributing substantially to the burden and, by implication, to radiative
forcing and diminution of surface irradiance. Although the dominant sulfate
formation pathway in the domain as a whole is aqueous-phase reaction in
clouds (62%), in regions with minimum opportunity for aqueous-phase
reaction gas-phase oxidation is dominant, albeit with considerable
temporal variability depending on meteorological conditions. These
calculations highlight the importance of transoceanic transport of sulfate,
especially at the western margins of continents under the influence of
predominantly westerly transport winds. |
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