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Titel |
Can a global model reproduce observed trends in summertime surface ozone levels? |
VerfasserIn |
S. Koumoutsaris, I. Bey |
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 ; 12, no. 15 ; Nr. 12, no. 15 (2012-08-02), S.6983-6998 |
Datensatznummer |
250011366
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Publikation (Nr.) |
copernicus.org/acp-12-6983-2012.pdf |
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Zusammenfassung |
Quantifying trends in surface ozone concentrations is critical for assessing
pollution control strategies. Here we use observations and results from a
global chemical transport model to examine the trends (1991–2005) in daily
maximum 8-h average concentrations in summertime surface ozone at rural sites
in Europe and the United States (US). We find a decrease in observed ozone
concentrations at the high end of the probability distribution at many of the
sites in both regions. The model attributes these trends to a decrease in
local anthropogenic ozone precursors, although simulated decreasing trends
are overestimated in comparison with observed ones. The low end of observed
distribution show small upward trends over Europe and the western US and
downward trends in Eastern US. The model cannot reproduce these observed
trends, especially over Europe and the western US. In particular, simulated
changes between the low and high end of the distributions in these two
regions are not significant. Sensitivity simulations indicate that emissions
from far away source regions do not affect significantly summer ozone trends at
both ends of the distribution in both Europe and US. Possible reasons
for discrepancies between observed and simulated trends are discussed. |
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