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| Titel |
Sensitivity of polar stratospheric ozone loss to uncertainties in chemical reaction kinetics |
| VerfasserIn |
S. R. Kawa, R. S. Stolarski, P. A. Newman, A. R. Douglass, M. Rex, D. J. Hofmann, M. L. Santee, K. Frieler |
| 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 ; 9, no. 22 ; Nr. 9, no. 22 (2009-11-16), S.8651-8660 |
| Datensatznummer |
250007749
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| Publikation (Nr.) |
 copernicus.org/acp-9-8651-2009.pdf |
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| Zusammenfassung |
| The impact and significance of uncertainties in model calculations of
stratospheric ozone loss resulting from known uncertainty in chemical
kinetics parameters is evaluated in trajectory chemistry simulations for the
Antarctic and Arctic polar vortices. The uncertainty in modeled ozone loss
is derived from Monte Carlo scenario simulations varying the kinetic
(reaction and photolysis rate) parameters within their estimated uncertainty
bounds. Simulations of a typical winter/spring Antarctic vortex scenario and
Match scenarios in the Arctic produce large uncertainty in ozone loss rates
and integrated seasonal loss. The simulations clearly indicate that the
dominant source of model uncertainty in polar ozone loss is uncertainty in
the Cl2O2 photolysis reaction, which arises from uncertainty in
laboratory-measured molecular cross sections at atmospherically important
wavelengths. This estimated uncertainty in JCl2O2 from laboratory
measurements seriously hinders our ability to model polar ozone loss within
useful quantitative error limits. Atmospheric observations, however, suggest
that the Cl2O2 photolysis uncertainty may be less than that
derived from the lab data. Comparisons to Match, South Pole ozonesonde, and
Aura Microwave Limb Sounder (MLS) data all show that the nominal recommended
rate simulations agree with data within uncertainties when the
Cl2O2 photolysis error is reduced by a factor of two, in line with
previous in situ ClOx measurements. Comparisons to simulations using
recent cross sections from Pope et al. (2007) are outside the constrained
error bounds in each case. Other reactions producing significant sensitivity
in polar ozone loss include BrO + ClO and its branching ratios. These
uncertainties challenge our confidence in modeling polar ozone depletion and
projecting future changes in response to changing halogen emissions and
climate. Further laboratory, theoretical, and possibly atmospheric studies
are needed. |
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