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| Titel |
Observation-based assessment of stratospheric fractional release, lifetimes, and ozone depletion potentials of ten important source gases |
| VerfasserIn |
J. C. Laube, A. Keil, H. Bönisch, A. Engel, T. Röckmann, C. M. Volk, W. T. Sturges |
| 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 ; 13, no. 5 ; Nr. 13, no. 5 (2013-03-08), S.2779-2791 |
| Datensatznummer |
250018483
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| Publikation (Nr.) |
 copernicus.org/acp-13-2779-2013.pdf |
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| Zusammenfassung |
| Estimates of the recovery time of stratospheric ozone heavily rely on the
exact knowledge of the processes that lead to the decomposition of the
relevant halogenated source gases. Crucial parameters in this context are
fractional release factors (FRFs) as well as stratospheric lifetimes and
ozone depletion potentials (ODPs). We here present data from the analysis of
air samples collected between 2009 and 2011 on board research aircraft flying
in the mid- and high-latitude stratosphere and infer the above-mentioned
parameters for ten major source gases: CFCl3 (CFC-11),
CF2Cl2 (CFC-12), CF2ClCFCl2 (CFC-113),
CCl4 (carbon tetrachloride), CH3CCl3 (methyl chloroform),
CHF2Cl (HCFC-22), CH3CFCl2 (HCFC-141b), CH3CF2Cl
(HCFC-142b), CF2ClBr (H-1211), and CF3Br (H-1301). The inferred
correlations of their FRFs with mean ages of air reveal less decomposition as
compared to previous studies for most compounds. When using the calculated
set of FRFs to infer equivalent stratospheric chlorine, we find a reduction of
more than 20% as compared to the values inferred in the most recent
Scientific Assessment of Ozone Depletion by the World Meteorological
Organisation (WMO, 2011). We also note that FRFs and their correlations with
mean age are not generally time-independent as often assumed. The
stratospheric lifetimes were calculated relative to that of CFC-11.
Within our uncertainties the ratios between stratospheric lifetimes inferred
here agree with the values in recent WMO reports except for CFC-11,
CFC-12 and CH3CCl3. Finally, we calculate lower ODPs than
recommended by WMO for six out of ten compounds, with changes most pronounced
for the three HCFCs. Collectively these newly calculated values may have
important implications for the severity and recovery time of stratospheric
ozone loss. |
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