CERC — Environmental Software and Services

ADMS-Urban RML icon

ADMS-Urban Regional Model Link

Automated system for nesting ADMS-Urban in regional air quality models

Model input data

Meso-scale meteorological model data

The ADMS-Urban RML system 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. The ADMS-Urban RML Controller automatically identifies the correct data file for each hour of the modelling period following a user-defined date- and time-dependent naming convention.

Regional model concentration data

At present the ADMS-Urban RML is compatible with output files from the CMAQ, CAMx (converted to I/O API), CHIMERE and EMEP4UK 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. The ADMS-Urban RML system is designed to be extendable to other regional models. Please contact CERC if you would like to use the ADMS-Urban RML system 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 the ADMS-Urban RML system, 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.

Local modelling parameters

ADMS-Urban model parameter files 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 the ADMS-Urban RML system 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, intelligent gridding can be included in the ADMS-Urban RML system in order to create high-resolution contour plots of concentrations.

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