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| Titel |
Evaluation of simulated photochemical partitioning of oxidized nitrogen in the upper troposphere |
| VerfasserIn |
B. H. Henderson, R. W. Pinder, J. Crooks, R. C. Cohen, W. T. Hutzell, G. Sarwar, W. S. Goliff, W. R. Stockwell, A. Fahr, R. Mathur, A. G. Carlton, W. Vizuete |
| 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 ; 11, no. 1 ; Nr. 11, no. 1 (2011-01-14), S.275-291 |
| Datensatznummer |
250009071
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| Publikation (Nr.) |
 copernicus.org/acp-11-275-2011.pdf |
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| Zusammenfassung |
| Regional and global chemical transport models underpredict
NOx (NO + NO2) in the upper troposphere where
it is a precursor to the greenhouse gas ozone. The
NOx bias has been shown in model evaluations using
aircraft data (Singh et al., 2007) and total column NO2
(molecules cm−2) from satellite observations
(Napelenok et al., 2008). The causes of NOx
underpredictions have yet to be fully understood due to the
interconnected nature of simulated emission, transport, and
chemistry processes. Recent observation-based studies, in
the upper troposphere, identify
chemical rate coefficients as a potential source of error
(Olson et al., 2006; Ren et al., 2008). Since typical
chemistry evaluation techniques are not available for upper
tropospheric conditions, this study develops an evaluation
platform from in situ observations, stochastic convection, and
deterministic chemistry. We derive a stochastic convection
model and optimize it using two simulated datasets of time
since convection, one based on meteorology, and the other on
chemistry. The chemistry surrogate for time since convection
is calculated using seven different chemical mechanisms, all
of which predict shorter time since convection than our
meteorological analysis. We evaluate chemical simulations by
inter-comparison and by pairing results with observations
based on NOx:HNO3, a photochemical aging
indicator. Inter-comparison reveals individual chemical
mechanism biases and recommended updates. Evaluation against
observations shows that all chemical mechanisms overpredict
NOx removal relative to long-lived methanol and carbon
monoxide. All chemical mechanisms underpredict observed
NOx by at least 30%, and further evaluation is
necessary to refine simulation sensitivities to initial
conditions and chemical rate uncertainties. |
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