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| Titel |
The impacts of volcanic aerosol on stratospheric ozone and the Northern Hemisphere polar vortex: separating radiative-dynamical changes from direct effects due to enhanced aerosol heterogeneous chemistry |
| VerfasserIn |
S. Muthers, F. Arfeuille, C. C. Raible, E. Rozanov |
| 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. 20 ; Nr. 15, no. 20 (2015-10-16), S.11461-11476 |
| Datensatznummer |
250120099
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| Publikation (Nr.) |
 copernicus.org/acp-15-11461-2015.pdf |
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| Zusammenfassung |
| After major volcanic eruptions the enhanced aerosol causes ozone changes due
to greater heterogeneous chemistry on the particle surfaces (HET-AER) and
from dynamical effects related to the radiative heating of the lower
stratosphere (RAD-DYN). We carry out a series of experiments with an
atmosphere–ocean–chemistry–climate model to assess how these two processes
change stratospheric ozone and Northern Hemispheric (NH) polar vortex
dynamics. Ensemble simulations are performed under present day and
preindustrial conditions, and with aerosol forcings representative of
different eruption strength, to investigate changes in the response
behaviour. We show that the halogen component of the HET-AER effect dominates
under present-day conditions with a global reduction of ozone
(−21 DU for the strongest eruption) particularly at high latitudes,
whereas the HET-AER effect increases stratospheric ozone due to N2O5
hydrolysis in a preindustrial atmosphere (maximum anomalies +4 DU).
The halogen-induced ozone changes in the present-day atmosphere offset part
of the strengthening of the NH polar vortex during mid-winter (reduction of
up to −16 m s-1 in January) and slightly amplify the dynamical
changes in the polar stratosphere in late winter (+11 m s-1 in
March). The RAD-DYN mechanism leads to positive column ozone anomalies which
are reduced in a present-day atmosphere by amplified polar ozone depletion
(maximum anomalies +12 and +18 DU for present day and
preindustrial, respectively). For preindustrial conditions, the ozone
response is consequently dominated by RAD-DYN processes, while under present-day conditions, HET-AER effects dominate. The dynamical response of the
stratosphere is dominated by the RAD-DYN mechanism showing an intensification
of the NH polar vortex in winter (up to +10 m s-1 in January).
Ozone changes due to the RAD-DYN mechanism slightly reduce the response of
the polar vortex after the eruption under present-day conditions. |
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