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| Titel |
Application of WRF/Chem-MADRID and WRF/Polyphemus in Europe – Part 2: Evaluation of chemical concentrations and sensitivity simulations |
| VerfasserIn |
Y. Zhang, K. Sartelet, S. Zhu, W. Wang, S.-Y. Wu, X. Zhang, K. Wang, P. Tran, C. Seigneur, Z.-F. Wang |
| 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 ; 13, no. 14 ; Nr. 13, no. 14 (2013-07-22), S.6845-6875 |
| Datensatznummer |
250018768
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| Publikation (Nr.) |
 copernicus.org/acp-13-6845-2013.pdf |
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| Zusammenfassung |
An offline-coupled model (WRF/Polyphemus) and an online-coupled model
(WRF/Chem-MADRID) are applied to simulate air quality in July 2001 at
horizontal grid resolutions of 0.5° and
0.125° over Western Europe. The model performance is
evaluated against available surface and satellite observations. The two
models simulate different concentrations in terms of domainwide performance
statistics, spatial distribution, temporal variations, and column abundance.
WRF/Chem-MADRID at 0.5° gives higher values than
WRF/Polyphemus for the domainwide mean and over polluted regions in Central
and southern Europe for all surface concentrations and column variables
except for the tropospheric ozone residual (TOR). Compared with
observations, WRF/Polyphemus gives better statistical performance for daily
HNO3, SO2, and NO2 at the European Monitoring and Evaluation Programme (EMEP) sites, maximum 1 h O3 at
the AirBase sites, PM2.5 at the AirBase sites, maximum 8 h O3 and
PM10 composition at all sites, column abundance of CO, NO2, TOR,
and aerosol optical depth (AOD), whereas WRF/Chem-MADRID gives better statistical performance for
NH3, hourly SO2, NO2, and O3 at the AirBase and BDQA (Base de données de la qualité de l'air)
sites, maximum 1 h O3 at the BDQA and EMEP sites, and PM10 at all
sites. WRF/Chem-MADRID generally reproduces well the observed high hourly
concentrations of SO2 and NO2 at most sites except for extremely
high episodes at a few sites, and WRF/Polyphemus performs well for hourly
SO2 concentrations at most rural or background sites where pollutant
levels are relatively low, but it underpredicts the observed hourly NO2
concentrations at most sites. Both models generally capture well the daytime
maximum 8 h O3 concentrations and diurnal variations of O3 with
more accurate peak daytime and minimal nighttime values by WRF/Chem-MADRID,
but neither model reproduces extremely low nighttime O3 concentrations at several urban and suburban sites due to underpredictions
of NOx and thus insufficient titration of O3 at night.
WRF/Polyphemus gives more accurate concentrations of PM2.5, and
WRF/Chem-MADRID reproduces better the observations of PM10
concentrations at all sites. The differences between model predictions and
observations are mostly caused by inaccurate representations of emissions of
gaseous precursors and primary PM species, as well as biases in the
meteorological predictions. The differences in model predictions are caused
by differences in the heights of the first model layers and thickness of
each layer that affect vertical distributions of emissions, model treatments
such as dry/wet deposition, heterogeneous chemistry, and aerosol and cloud,
as well as model inputs such as emissions of soil dust and sea salt and
chemical boundary conditions of CO and O3 used in both models.
WRF/Chem-MADRID shows a higher sensitivity to grid resolution than
WRF/Polyphemus at all sites. For both models, the use of a finer grid
resolution generally leads to an overall better statistical performance for
most variables, with greater spatial details and an overall better agreement
in temporal variations and magnitudes at most sites. The use of online
biogenic volatile organic compound (BVOC) emissions gives better statistical
performance for hourly and maximum 8 h O3 and PM2.5 and generally
better agreement with their observed temporal variations at most sites.
Because it is an online model, WRF/Chem-MADRID offers the advantage of
accounting for various feedbacks between meteorology and chemical species.
However, this model comparison suggests that atmospheric pollutant
concentrations are most sensitive in state-of-the-science air quality models
to vertical structure, inputs, and parameterizations for dry/wet removal of
gases and particles in the model. |
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