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| Titel |
Regional CO pollution and export in China simulated by the high-resolution nested-grid GEOS-Chem model |
| VerfasserIn |
D. Chen, Y. Wang, M. B. McElroy, K. He, R. M. Yantosca, P. Sager |
| 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. 11 ; Nr. 9, no. 11 (2009-06-12), S.3825-3839 |
| Datensatznummer |
250007369
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| Publikation (Nr.) |
 copernicus.org/acp-9-3825-2009.pdf |
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| Zusammenfassung |
| An updated version of the nested-grid GEOS-Chem model is developed allowing
for higher horizontal (0.5°×0.667°) resolution as compared
to global models. CO transport over a heavily polluted region, the
Beijing-Tianjin-Hebei (BTH) city cluster in China, and the pattern of
outflow from East China in summertime are investigated. Comparison of the
nested-grid with global models indicates that the fine-resolution
nested-grid model is capable of resolving individual cities with high
associated emission intensities. The nested-grid model indicates the
presence of a high CO column density over the Sichuan Basin in summer,
attributable to the low-level stationary vortex associated with the Basin's
topographical features. The nested-grid model provides good agreement also
with measurements from a suburban monitoring site in Beijing during summer
2005. Tagged CO simulation results suggest that regional emissions make
significant contributions to elevated CO levels over Beijing on polluted
days and that the southeastward moving cyclones bringing northwest winds to
Beijing are the key meteorological mechanisms responsible for dispersion of
pollution over Beijing in summer. Overall CO fluxes to the NW Pacific from
Asia are found to decrease by a factor of 3–4 from spring to summer. Much of
the seasonal change is driven by decreasing fluxes from India and Southeast
Asia in summer, while fluxes from East China are only 30% lower in summer
than in spring. Compared to spring, summertime outflow from Chinese source
regions is strongest at higher latitudes (north of 35° N). The deeper
convection in summer transporting CO to higher altitudes where export is
more efficient is largely responsible for enhanced export in summer. |
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