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| Titel |
Upgrading photolysis in the p-TOMCAT CTM: model evaluation and assessment of the role of clouds |
| VerfasserIn |
A. Voulgarakis, N. H. Savage, O. Wild, G. D. Carver, K. C. Clemitshaw, J. A. Pyle |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 2, no. 1 ; Nr. 2, no. 1 (2009-05-20), S.59-72 |
| Datensatznummer |
250000422
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| Publikation (Nr.) |
 copernicus.org/gmd-2-59-2009.pdf |
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| Zusammenfassung |
| A new version of the p-TOMCAT Chemical Transport Model (CTM) which includes an improved photolysis code,
Fast-JX, is validated. Through offline testing we show that
Fast-JX captures well the observed J(NO2) and J(O1D) values obtained at Weybourne and during a flight
above the Atlantic, though with some overestimation of J(O1D)
when comparing to the aircraft data. By comparing
p-TOMCAT output of CO and ozone with measurements, we find that the inclusion of Fast-JX in
the CTM strongly improves the latter's ability to capture the seasonality and
levels of tracers' concentrations. A probability distribution analysis demonstrates that photolysis
rates and oxidant (OH, ozone) concentrations cover a broader range of
values when using Fast-JX instead of the standard photolysis scheme. This is not only driven by
improvements in the seasonality of cloudiness but also even more
by the better representation of cloud spatial variability. We use three different cloud treatments to study
the radiative effect of clouds on the
abundances of a range of tracers and find only modest effects on a global scale. This is consistent with the most
relevant recent study. The new version of the validated
CTM will be used for a variety of future studies examining the variability of tropospheric composition
and its drivers. |
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