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| Titel |
Representing ozone extremes in European megacities: the importance of resolution in a global chemistry climate model |
| VerfasserIn |
Z. S. Stock, M. R. Russo, J. A. Pyle |
| 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 ; 14, no. 8 ; Nr. 14, no. 8 (2014-04-17), S.3899-3912 |
| Datensatznummer |
250118624
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| Publikation (Nr.) |
 copernicus.org/acp-14-3899-2014.pdf |
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| Zusammenfassung |
The continuing growth of the world's urban population has led to an
increasing number of cities with more than 10 million inhabitants. The higher
emissions of pollutants, coupled to higher population density, makes
predictions of air quality in these megacities of particular importance from
both a science and a policy perspective. Global climate models are typically
run at coarse resolution to enable both the efficient running of long time
integrations, and the ability to run multiple future climate scenarios.
However, when considering surface ozone concentrations at the local scale,
coarse resolution can lead to inaccuracies arising from the highly nonlinear
ozone chemistry and the sensitivity of ozone to the distribution of its
precursors on smaller scales. In this study, we use UM-UKCA, a global
atmospheric chemistry model, coupled to the UK Met Office Unified Model, to
investigate the impact of model resolution on tropospheric ozone, ranging
from global to local scales. We focus on the model's ability to represent the
probability of high ozone concentrations in the summer and low ozone
concentrations, associated with polluted megacity environments, in the
winter, and how this varies with horizontal resolution.
We perform time-slice integrations with two model configurations at typical
climate resolution (CR, ~150 km) and at a higher resolution
(HR, ~40 km). The CR configuration leads to overestimation of
ozone concentrations on both regional and local scales, while it gives
broadly similar results to the HR configuration on the global scale. The HR
configuration is found to produce a more realistic diurnal cycle of ozone
concentrations and to give a better representation of the probability density
function of ozone values in urban areas such as the megacities of London and
Paris. We find the observed differences in model behaviour between CR and HR
configurations to be largely caused by chemical differences during the winter
and meteorological differences during the summer. |
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