• Modelling System Information
• Current Developments
• References

Modelling System Information

AQM.cat is an air quality modelling system (Arasa et al., 2009) developed by the mesoscale and microscale atmospheric modelling and research group (MAiR). AQM.cat is based on coupling the Eulerian models MM5, MNEQA and CMAQ.

Daily simulations are made in the computational system belonging to the Department of Astronomy and Meteorology of the University of Barcelona. The different models coupled in the AQM.cat system are executed for three domains focusing on the area of Catalonia, with different vertical and horizontal resolution

D1 Domain	D2 Domain	D3 Domain
Horizontal resolution 27 km	Horizontal resolution 9 km	Horizontal resolution 3 km
31 vertical levels	31 vertical levels	31 vertical levels
Daily forecasts 48 h	Daily forecasts 48 h	Daily forecasts 48 h
Starting at 00 UTC	Starting at 00 UTC	Starting at 00 UTC

• The MM5 model (Grell et al., 1994) is a limited-area, non-hydrostatic, terrain-following sigma-coordinate model designed to simulate or predict mesoscale atmospheric circulation. The MM5 modelling system software has been developed at Penn State and NCAS as a community of mesoscale models with contributions from users worldwide. The MM5 modelling system software is freely provided and supported by the Mesoscale Prediction Group in the Mesoscale and Microscale Meteorology Division, NCAR. MM5 is one of the most used models and is nowadays used jointly with the WRF model in numerical weather prediction, offering high reliability. The model solves primitive equations of atmosphere using different physical parameterisations, such as those for boundary layer, surface layer, radiation or cumulus. Model initialisation requires initial and boundary conditions, which are provided by the Catalan Meteorological Office (Servei Meteorològic de Catalunya, SMC). AQM.cat simulations are made using MM5 version 3.7. MM5 is executed for three nested domains (D1, D2 and D3), so meteorological processes which take place in one of these domains may also influence the other domains.
• MNEQA is an emissions model developed by the MAiR group and includes emissions from both natural sources (particles from dust or hydrocarbons emitted by vegetation) and anthropogenic sources (mainly traffic and industry). As nested domains are commonly applied to air quality modelling systems, because the constituent meteorological, emission and photochemistry models must deal with grid variability and various domain ranges, MNEQA methodology differs from one domain to another. For smaller domains such as D1, the MNEQA model uses bottom-up methodology to calculate pollutant emissions, which involves working out each type of source in a particular way using local information. For larger domains (D2 and D3), MNEQA uses top-down methodology, which incorporates pollutant emissions from the European annual inventory EMEP/CORINAIR¹ into the model. The basis of the disaggregation method is the soil uses CLC2000 (Corine LandClass 2000) with 250 m resolution, coupled with different statistical functions, including socio-economic variables. This latter methodology is used in nested air quality systems when there is no available information regarding emissions in specific areas. Nowadays MAiR works with MNEQA version 4.0, including as primary pollutants initrogen oxides (NOx), volatile organic compounds (COVS), carbon monoxide (CO), sulphur dioxide (SO2) and particles smaller than 10 µm and 2.5 µm (PM10 and PM2.5, respectively).
• CMAQ (Byun & Ching, 1999) is a photochemical model developed by the Environmental Protection Agency (EPA). The software is freely provided, so users can make the most suitable adjustments. Simulations made by the MAiR group correspond to version 4.6. CMAQ solves the diffusivity equation for different pollutants and works in one-way nesting. As inputs the model requires meteorological data provided by meteorological model MM5 and emissions data provided by MNEQA. Simulations made with the CMAQ model supplied pollutant concentrations of gases and particles, with different time steps and for all configuration domains. The chemical mechanism used in simulations is CBM-V for gases and AERO4 for particles.

Current Developments

• Coupling the WRF model to the photochemical model CMAQ, in order to have a second air quality model modelling system WFR/MNEQA/CMAQ.
• Coupling MNEQA to Chem in order to have a third air quality modelling system WRF/MNEQA/Chem.
• Verification and comparison of the previous air quality systems: WFR/MNEQA/CMAQ and WRF/MNEQA/Chem.
• Updating the emission model MNEQA.
• Coupling global model outputs to the previous air quality systems.

References

Arasa, R., Soler, M.R., Ortega, S., Olid, M., Merino, M., 2009. A performance evaluation of MM5/MNEQA/CMAQ air quality modelling system to forecast ozone concentrations in Catalonia.Tethys. DOI: 10.3369/tethys.2010.7.02

Byun, D.W., Ching, J.K.S. Editors, 1999. Science Algorithms of the EPA Models-3 Community Multiscale Air Quality (CMAQ) Modeling System. Environmental Protection Agency.

European Environmental Agency, 2007. EMEP/CORINAIR Emission Inventory Guidebook. Technical Report No. 16/2007. http://reports.eea.europa.eu/EMEPCORINAIR5/en/page-002.html

Grell, G.A., Dudhia, J., Stauffer, D.R., 1994. A description of the fifth-generation Penn State/NCAR mesoscale model (MM5). MM5 Technical Note NCAR/TN-398+STR, 117pp.

Ortega, S., Soler, M.R., Alarcón, M., Arasa, R., 2009. MNEQA, an emissions model for photochemical simulations. Atmospheric Environment, 43, 3670-3681.

European Environmental Agency, 2007. EMEP/CORINAIR Emission Inventory Guidebook. Technical Report No.16/2007. Available in: http://reports.eea.europa.eu/EMEPCORINAIR5/en/page-002.html