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| Titel |
Oceanic bromoform emissions weighted by their ozone depletion potential |
| VerfasserIn |
S. Tegtmeier, F. Ziska, I. Pisso, B. Quack, G. J. M. Velders, X. Yang, K. Krüger |
| 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 ; 15, no. 23 ; Nr. 15, no. 23 (2015-12-10), S.13647-13663 |
| Datensatznummer |
250120217
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| Publikation (Nr.) |
 copernicus.org/acp-15-13647-2015.pdf |
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| Zusammenfassung |
| At present, anthropogenic
halogens and oceanic emissions of very short-lived substances (VSLSs) both
contribute to the observed stratospheric ozone depletion. Emissions of the
long-lived anthropogenic halogens have been reduced and are currently
declining, whereas emissions of the biogenic VSLSs are expected to increase
in future climate due to anthropogenic activities affecting oceanic
production and emissions. Here, we introduce a new approach for assessing the
impact of oceanic halocarbons on stratospheric ozone by calculating their
ozone depletion potential (ODP)-weighted emissions. Seasonally and spatially
dependent, global distributions are derived within a case-study framework for
CHBr3 for the period 1999–2006. At present, ODP-weighted emissions of
CHBr3 amount up to 50 % of ODP-weighted anthropogenic emissions of
CFC-11 and to 9 % of all long-lived ozone depleting halogens. The
ODP-weighted emissions are large where strong oceanic emissions coincide with
high-reaching convective activity and show pronounced peaks at the Equator
and the coasts with largest contributions from the Maritime Continent and
western Pacific Ocean. Variations of tropical convective activity
lead to seasonal shifts in the spatial distribution of the trajectory-derived
ODP with the updraught mass flux, used as a proxy for trajectory-derived ODP,
explaining 71 % of the variance of the ODP distribution. Future climate
projections based on the RCP 8.5 scenario suggest a 31 % increase of the
ODP-weighted CHBr3 emissions by 2100 compared to present values. This
increase is related to a larger convective updraught mass flux in the upper
troposphere and increasing emissions in a future climate. However, at the
same time, it is reduced by less effective bromine-related ozone depletion
due to declining stratospheric chlorine concentrations. The comparison of the
ODP-weighted emissions of short- and long-lived halocarbons provides a new
concept for assessing the overall impact of oceanic halocarbon emissions on
stratospheric ozone depletion for current conditions and future projections. |
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