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| Titel |
A regional air quality forecasting system over Europe: the MACC-II daily ensemble production |
| VerfasserIn |
V. Marecal, V.-H. Peuch, C. Andersson, S. Andersson, J. Arteta, M. Beekmann, A. Benedictow, R. Bergstrom, B. Bessagnet, A. Cansado, F. Chéroux, A. Colette, A. Coman, R. L. Curier, H. A. C. Denier van der Gon, A. Drouin, H. Elbern, E. Emili, R. J. Engelen, H. J. Eskes, G. Foret, E. Friese, M. Gauss, C. Giannaros, J. Guth, M. Joly, E. Jaumouillé, B. Josse, N. Kadygrov, J. W. Kaiser, K. Krajsek, J. Kuenen, U. Kumar, N. Liora, E. López, L. Malherbe, I. Martinez, D. Melas, F. Meleux, L. Menut, P. Moinat, T. Morales, J. Parmentier, A. Piacentini, M. Plu, A. Poupkou, S. Queguiner, L. Robertson, L. Rouïl, M. Schaap, A. Segers, M. Sofiev, L. Tarasson, M. Thomas, R. Timmermans, A. Valdebenito, P. van Velthoven, R. van Versendaal, J. Vira, A. Ung |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 8, no. 9 ; Nr. 8, no. 9 (2015-09-08), S.2777-2813 |
| Datensatznummer |
250116553
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| Publikation (Nr.) |
 copernicus.org/gmd-8-2777-2015.pdf |
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| Zusammenfassung |
This paper describes the pre-operational analysis and forecasting system
developed during MACC (Monitoring Atmospheric Composition and Climate) and
continued in the MACC-II (Monitoring Atmospheric Composition and Climate:
Interim Implementation) European projects to provide air quality services
for the European continent. This system is based on seven state-of-the art
models developed and run in Europe (CHIMERE, EMEP, EURAD-IM, LOTOS-EUROS,
MATCH, MOCAGE and SILAM). These models are used to calculate multi-model
ensemble products. The paper gives an overall picture of its status at the
end of MACC-II (summer 2014) and analyses the performance of the multi-model
ensemble. The MACC-II system provides daily 96 h forecasts with hourly
outputs of 10 chemical species/aerosols (O3, NO2, SO2, CO,
PM10, PM2.5, NO, NH3, total NMVOCs (non-methane volatile organic compounds) and
PAN+PAN precursors) over eight vertical levels from the surface to 5 km height.
The hourly analysis at the surface is done a posteriori for the past day using a
selection of representative air quality data from European monitoring
stations.
The performance of the system is assessed daily, weekly and every 3 months
(seasonally) through statistical indicators calculated using the available
representative air quality data from European monitoring stations. Results
for a case study show the ability of the ensemble median to forecast
regional ozone pollution events. The seasonal performances of the individual
models and of the multi-model ensemble have been monitored since September
2009 for ozone, NO2 and PM10. The statistical indicators for ozone
in summer 2014 show that the ensemble median gives on
average the best performances compared to the seven models. There is very little degradation of
the scores with the forecast day but there is a marked diurnal cycle,
similarly to the individual models, that can be related partly to the
prescribed diurnal variations of anthropogenic emissions in the models.
During summer 2014, the diurnal ozone maximum is underestimated by the
ensemble median by about 4 μg m−3 on average. Locally, during the
studied ozone episodes, the maxima from the ensemble median are often lower
than observations by 30–50 μg m−3. Overall, ozone scores are
generally good with average values for the normalised indicators of 0.14 for
the modified normalised mean bias and of 0.30 for the fractional gross
error. Tests have also shown that the ensemble median is robust to reduction
of ensemble size by one, that is, if predictions are unavailable from one
model. Scores are also discussed for PM10 for winter 2013–1014. There
is an underestimation of most models leading the ensemble median to a
mean bias of −4.5 μg m−3. The ensemble median fractional gross
error is larger for PM10 (~ 0.52) than for ozone and
the correlation is lower (~ 0.35 for PM10 and
~ 0.54 for ozone). This is related to a larger spread of the seven
model scores for PM10 than for ozone linked to different levels of
complexity of aerosol representation in the individual models. In parallel,
a scientific analysis of the results of the seven models and of the ensemble
is also done over the Mediterranean area because of the specificity of its
meteorology and emissions.
The system is robust in terms of the production availability. Major efforts
have been done in MACC-II towards the operationalisation of all its
components. Foreseen developments and research for improving its
performances are discussed in the conclusion. |
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