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| Titel |
Uncertainties in modelling heterogeneous chemistry and Arctic ozone depletion in the winter 2009/2010 |
| VerfasserIn |
I. Wohltmann, T. Wegner, R. Müller, R. Lehmann, M. Rex, G. L. Manney, M. L. Santee, P. Bernath, O. Sumińska-Ebersoldt, F. Stroh, M. Hobe, C. M. Volk, E. Hösen, F. Ravegnani, A. Ulanovsky, V. Yushkov |
| 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. 8 ; Nr. 13, no. 8 (2013-04-17), S.3909-3929 |
| Datensatznummer |
250018589
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| Publikation (Nr.) |
 copernicus.org/acp-13-3909-2013.pdf |
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| Zusammenfassung |
| Stratospheric chemistry and denitrification are simulated for the Arctic
winter 2009/2010 with the Lagrangian Chemistry and Transport Model ATLAS.
A number of sensitivity runs is used to explore the impact of uncertainties in
chlorine activation and denitrification on the model results. In particular,
the efficiency of chlorine activation on different types of liquid aerosol
versus activation on nitric acid trihydrate clouds is examined.
Additionally, the impact of changes in reaction rate coefficients,
in the particle number density of polar stratospheric clouds,
in supersaturation, temperature or the extent of denitrification is
investigated.
Results are compared to satellite measurements
of MLS and ACE-FTS and to in-situ measurements onboard the Geophysica
aircraft during the RECONCILE measurement campaign.
It is shown that even large changes in the
underlying assumptions have only a small impact on the modelled ozone
loss, even though they can cause considerable differences in chemical
evolution of other species and in
denitrification. Differences in column ozone between the sensitivity runs
stay below 10% at the end of the winter.
Chlorine activation on liquid aerosols alone is able to explain the
observed magnitude and morphology of the mixing ratios of
active chlorine, reservoir gases and ozone.
This is even true for binary aerosols (no uptake of HNO3 from
the gas-phase allowed in the model). Differences in chlorine
activation between sensitivity runs are within 30%.
Current estimates of nitric acid trihydrate (NAT) number density and
supersaturation imply that, at least for this winter, NAT
clouds play a relatively small role compared to liquid clouds in
chlorine activation.
The change between different reaction rate coefficients for liquid
or solid clouds has only a minor impact on ozone loss
and chlorine activation in our sensitivity
runs. |
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