CERC — Environmental Software and Services

ADMS-Urban RML icon

MAQS

Multi-Model Air Quality System

Model input data

Meso-scale meteorological model data

MAQS uses meteorological data output files from the WRF meso-scale model. These files should contain the same data as used to run the regional air quality model, to ensure consistency between the regional and local components of the system. MAQS automatically identifies the correct data file for each hour of the modelling period following a user-defined date- and time-dependent naming convention. Please contact CERC if you would like to use the MAQS system with output from a different meteorological model.

Regional model concentration data

At present MAQS is compatible with output files from the CMAQ, CAMx (converted to I/O API), CHIMERE, EMEP4UK and WRF-Chem regional air quality models. The regional model output data should cover the required RML modelling domain with a buffer of one cell in each direction. The regional model grid must be regular in a projected coordinate system with units of metres. As the more detailed chemistry schemes used for regional modelling include a larger number of chemical species than are typically used in ADMS-Urban, a species map file is used to define how the regional model and ADMS-Urban pollutant species are related, including any required unit conversion factors. MAQS is designed to be extendable to other regional models. Please contact CERC if you would like to use MAQS with output from a different regional model.

Emissions

Image of Hong Kong NO2 emissions

NO2 emissions data visualised in the ADMS Mapper

In addition to the standard emissions data which is required to model an urban area using ADMS-Urban, for MAQS, gridded emissions data consistent with that used in the regional model must be processed in order to obtain valid nesting background concentrations. Both the total emission rates and the time-variation of emissions should be matched as closely as possible to the regional model equivalents. 3D gridded emissions as used in the CMAQ and WRF-Chem models can automatically be converted for use in ADMS-Urban.

Local modelling parameters

ADMS-Urban model parameter file(s) must be set up containing local source emissions, for example explicitly-modelled road sources, and specification of the required output locations and pollutant species.

Model output data

The output files from MAQS contain hourly concentrations at each output location in the portable netCDF format. The system is also supplied with a utility to extract statistics such as percentiles to ADMS-format text files, which can then be used in the standard ADMS-Urban contour plotting utilities and the Model Evaluation Toolkit.

As with ADMS-Urban, source-oriented gridding can be included in MAQS in order to create high-resolution contour plots of concentrations.

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