The aerosol distribution in Europe derived with the Community Multiscale Air Quality (CMAQ) model: comparison to near surface in situ and sunphotometer measurements

Abstract

Abstract. The aerosol distribution in Europe was simulated with the Community Multiscale Air Quality (CMAQ) model system version 4.5 for the years 2000 and 2001. The results were compared with daily averages of PM 10 measurements taken in the framework of EMEP and with aerosol optical depth (AOD) values measured within AERONET. The modelled total aerosol mass is typically about 30-60% lower than the corresponding measurements. However a comparison of the chemical composition of the aerosol revealed a considerably better agreement between the modelled and the measured aerosol components for ammonium, nitrate and sulfate, which are on average only 15-20% underestimated. Sligthly worse agreement was determined for sea salt, that was only avaliable at two sites. The largest discrepancies result from the aerosol mass which was not chemically specified by the measurements. The agreement between measurements and model is better in winter than in summer. The modelled organic aerosol mass is higher in summer than in winter but it is significantly underestimated by the model. This could be one of the main reasons for the discrepancies between measurements and model results. The other is that primary coarse particles are underestimated in the emissions. The probability distribution function of the PM 10 measurements follows a log-normal distribution at most sites. The model is only able to reproduce this distribution function at non-coastal low altitude stations. The AOD derived from the model results is 20-70% lower than the values observed within AERONET. This is mainly attributed to the missing aerosol mass in the model. The day-to-day variability of the AOD and the logCorrespondence to: V. Matthias (volker.matthias@gkss.de) normal distribution functions are quite well reproduced by the model. The seasonality on the other hand is underestimated by the model results because better agreement is achieved in winter.

Aerosols in the CALIOPE air quality modelling system: evaluation and analysis of PM levels, optical depths and chemical composition over Europe

“…The observed values are approximately a factor of 4 higher than the modelled values. This factor is higher than that obtained by Matthias (2008) at Birkenes in 2001 (factor of 3) partly because carbonaceous particles from biomass burning emissions were taken into account in the aforementioned study. There are other studies that demonstrate that SOA are underestimated by current models by a factor of 6 (Volkamer et al, 2006).…”

“…Pay et al (2010) found a positive mean bias for SO 2 which suggests that SO 2− 4 formation in the model is often limited by oxidant availability and not always by SO 2 availability. Winter underestimation of sulpahte is a common issue in most European models representing a direct couplet of sulfur chemistry with photochemistry and has been previously detected with CMAQv4.5 over Europe (Matthias, 2008). This feature may be explained by a lack of model calculated oxidants or missing reactions (Kasibhatla et al, 1997).…”

“…Many studies have recognized the difficulty of models to simulate the mass of PM over Europe (e.g. Matthias, 2008;Pay et al, 2010). The underestimation of PM 10 is, among others, the result of a lack of fugitive dust emissions, resuspended matter, a possible underestimation of primary carbonaceous particles, the inaccuracy of SOA formation, the difficulty of representing primary PM emission from wood burning and other sources not considered in the emission inventory as pollutant sources over North Africa (Rodríguez et al, 2011) and a more general lack of process knowledge on aerosol removal and dispersion and transport processes.…”

Modelling of primary aerosols in the chemical transport model MOCAGE: development and evaluation of aerosol physical parameterizations

“…The unspecified primary anthropogenic aerosols are not implemented in the configuration of the model used in this study, because they are not present in the emission inventories that we used, but they can be found in some models (e.g. Matthias, 2008).…”

Application of WRF-Chem to forecasting PM<SUB align="right">10 concentration over Poland

“…The majority of CTMs are offline models meaning that the meteorology is calculated prior to the chemistry such as CHIMEREv4.5 (Bessagnet et al, 2008;Pay et al, 2010), CMAQ (Matthias, 2008) or EMEP (Simpson et al, 2012;van Loon et al, 2007). Usually, the meteorology for these models is available at a 1 h, 3 h or 6 h resolution.…”