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| Titel |
The effects of a solar eclipse on photo-oxidants in different areas of China |
| VerfasserIn |
J.-B. Wu, Z. F. Wang, W. Zhang, H. B. Dong, X. L. Pan, J. Li, C.-Y. Lin, P. H. Xie |
| 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. 15 ; Nr. 11, no. 15 (2011-08-08), S.8075-8085 |
| Datensatznummer |
250009992
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| Publikation (Nr.) |
 copernicus.org/acp-11-8075-2011.pdf |
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| Zusammenfassung |
| This study investigates the effects of the total solar eclipse of 22 July
2009 on surface ozone and other photo-oxidants over China. A box model was
used to study the sensitivity of ozone to the limb darkening effect during
an eclipse event, and to show that the impact on ozone is small (less than
0.5 %). In addition, the regional model WRF-Chem was applied to study the
effects of the eclipse on meteorological and chemical parameters, focusing
on different regions in China. Chemical and meteorological observations were
used to validate the model and to show that it can capture the effects of
the total solar eclipse well. Model calculations show distinct differences
in the spatial distributions of meteorological and chemical parameters with
and without the eclipse. The maximum impacts of the eclipse occur over the
area of totality, where there is a decrease in surface temperature of 1.5 °C and decrease in wind speed of 1 m s−1. The maximum impacts on
atmospheric pollutants occur over parts of north and east China where
emissions are greater, with an increase of 5 ppbv in NO2 and 25 ppbv in
CO and a decrease of 10 ppbv in O3 and 4 ppbv in NO. This study also
demonstrates the effects of the solar eclipse on surface photo-oxidants in
different parts of China. Although the sun was obscured to a smaller extent
in polluted areas than in clean areas, the impacts of the eclipse in
polluted areas are greater and last longer than they do in clean areas. In
contrast, the change in radical concentrations (OH, HO2 and NO3)
in clean areas is much larger than in polluted areas mainly because of the
limited source of radicals in these areas. The change in radical
concentrations during the eclipse reveals that nighttime chemistry dominates
in both clean and polluted areas. As solar eclipses provide a natural
opportunity to test more thoroughly our understanding of atmospheric
chemistry, especially that governed by photolysis, a comprehensive
experimental campaign during a future solar eclipse is highly desirable. |
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