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| Titel |
Simulation of Mexico City plumes during the MIRAGE-Mex field campaign using the WRF-Chem model |
| VerfasserIn |
X. Tie, S. Madronich, G. Li, Z. Ying, A. Weinheimer, E. Apel, T. Campos |
| 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. 14 ; Nr. 9, no. 14 (2009-07-17), S.4621-4638 |
| Datensatznummer |
250007506
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| Publikation (Nr.) |
 copernicus.org/acp-9-4621-2009.pdf |
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| Zusammenfassung |
| The quantification of tropospheric O3 production in the downwind of the
Mexico City plume is a major objective of the MIRAGE-Mex field campaign. We
used a regional chemistry-transport model (WRF-Chem) to predict the
distribution of O3 and its precursors in Mexico City and the
surrounding region during March 2006, and compared the model with in-situ
aircraft measurements of O3, CO, VOCs, NOx, and NOy
concentrations. The comparison shows that the model is capable of capturing
the timing and location of the measured city plumes, and the calculated
variability along the flights is generally consistent with the measured
results, showing a rapid increase in O3 and its precursors when city
plumes are detected. However, there are some notable differences between the
calculated and measured values, suggesting that, during transport from the
surface of the city to the outflow plume, ozone mixing ratios are
underestimated by about 0–25% during different flights. The calculated
O3-NOx, O3-CO, and O3-NOz correlations generally
agree with the measured values, and the analyses of these correlations
suggest that photochemical O3 production continues in the plume
downwind of the city (aged plume), adding to the O3 already produced in
the city and exported with the plume. The model is also used to quantify the
contributions to OH reactivity from various compounds in the aged plume.
This analysis suggests that oxygenated organics (OVOCs) have the highest OH
reactivity and play important roles for the O3 production in the aging
plume. Furthermore, O3 production per NOx molecule consumed
(O3 production efficiency) is more efficient in the aged plume than in
the young plume near the city. The major contributor to the high O3
production efficiency in the aged plume is the reaction RO2+NO. By
contrast, the reaction of HO2+NO is rather uniformly distributed in the
plume. |
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