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| Titel |
Re-analysis of tropospheric sulfate aerosol and ozone for the period 1980–2005 using the aerosol-chemistry-climate model ECHAM5-HAMMOZ |
| VerfasserIn |
L. Pozzoli, G. Janssens-Maenhout, T. Diehl, I. Bey, M. G. Schultz, J. Feichter, E. Vignati, F. Dentener |
| 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. 18 ; Nr. 11, no. 18 (2011-09-16), S.9563-9594 |
| Datensatznummer |
250010080
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| Publikation (Nr.) |
 copernicus.org/acp-11-9563-2011.pdf |
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| Zusammenfassung |
| Understanding historical trends of trace gas and aerosol distributions in the
troposphere is essential to evaluate the efficiency of existing
strategies to reduce air pollution and to design more efficient future air
quality and climate policies. We performed coupled photochemistry and aerosol
microphysics simulations for the period 1980–2005 using the
aerosol-chemistry-climate model ECHAM5-HAMMOZ, to assess our understanding of
long-term changes and inter-annual variability of the chemical composition of
the troposphere, and in particular of ozone and sulfate concentrations, for
which long-term surface observations are available. In order to separate the
impact of the anthropogenic emissions and natural variability on atmospheric
chemistry, we compare two model experiments, driven by the same ECMWF
re-analysis data, but with varying and constant anthropogenic emissions,
respectively. Our model analysis indicates an increase of ca. 1 ppbv
(0.055 ± 0.002 ppbv yr−1) in global average surface O3
concentrations due to anthropogenic emissions, but this trend is largely
masked by the larger O3 anomalies due to the variability of meteorology
and natural emissions. The changes in meteorology (not including
stratospheric variations) and natural emissions account for the 75 % of the
total variability of global average surface O3 concentrations. Regionally,
annual mean surface O3 concentrations increased by 1.3 and 1.6 ppbv over
Europe and North America, respectively, despite the large anthropogenic
emission reductions between 1980 and 2005. A comparison of winter and summer
O3 trends with measurements shows a qualitative agreement, except in North
America, where our model erroneously computed a positive trend. Simulated
O3 increases of more than 4 ppbv in East Asia and 5 ppbv in South Asia
can not be corroborated with long-term observations. Global average sulfate
surface concentrations are largely controlled by anthropogenic emissions.
Globally natural emissions are an important driver determining AOD
variations. Regionally, AOD decreased by 28 % over Europe, while it
increased by 19 % and 26 % in East and South Asia. The global radiative
perturbation calculated in our model for the period 1980–2005 was rather
small (0.05 W m−2 for O3 and 0.02 W m−2 for total aerosol
direct effect), but larger perturbations ranging from −0.54 to
1.26 W m−2 are estimated in those regions where anthropogenic
emissions largely varied. |
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