Quoted from: http://www.cerc.co.uk/environmental-software/ADMS-Urban-RML.html 

What is the ADMS-Urban Regional Model Link?

The ADMS-Urban Regional Model Link (ADMS-Urban RML) is an innovative automated system for nesting the high resolution air quality model ADMS-Urban in a regional air quality model such as CMAQ, CAMx, CHIMERE or EMEP4UK or WRF-Chem using meteorological data from the meso-scale WRF model. The output from the ADMS-Urban RML system comprises predictions of pollutant concentrations for an urban area, which take into account both regional and local pollutant transport and chemistry effects.

The main components of the ADMS-Urban RML system are the ADMS-Urban local dispersion model, Run Manager software for distributing ADMS-Urban runs across multiple machines and the ADMS-Urban RML Controller, which consists of a graphical user interface, control program and five utility programs.

Typical applications of the ADMS-Urban RML include:

• developing and testing the impact of regional and local air quality management policies on pollutant concentrations throughout a complex urban area
• assessments of the air quality impact from proposed developments
• exposure assessments
• provision of detailed street-scale air quality forecasts for an urban area in combination with a regional scale forecast for surrounding rural areas

Who uses the ADMS-Urban Regional Model Link?

Annual average NO2 concentrations calculated by the ADMS-Urban RML displayed within a larger regional model domain.

The ADMS-Urban RML system is for current users of regional air dispersion models who wish to increase the resolution of their modelling over urban areas to take account of street-scale concentration gradients in a computationally efficient way, and for users of ADMS-Urban who wish to take into account spatially-varying meteorology and background concentrations from regional modelling. The design of the system allows the regional modelling and the local modelling to be performed separately, facilitating collaborations between regional and local modelling specialists and allowing a single set of regional modelling data to be used to test many local modelling scenarios.

Pioneering uses of the ADMS-Urban Regional Model Link include:

• The ADMS-Urban RML has been set up to model the Hong Kong Special Administrative Region for the Hong Kong Environmental Protection Department. Regional model data was taken from the CAMx model run by researchers from the Hong Kong University of Science and Technology (HKUST). HKUST hope to extend their existing CMAQ and CAMx regional model air quality forecasting system to predict roadside concentrations by incorporating the ADMS-Urban RML system.
• Researchers at the University of Edinburgh’s Contemporary Climate group use the ADMS-Urban RML with the EMEP4UK regional model to investigate the effects of future climate scenarios on local air quality in London and across the UK.
• CERC’s partners in France, NUMTECH, are planning to combine their experience of using ADMS-Urban and the regional model CHIMERE by using the ADMS-Urban RML system to improve modelling of complex urban environments in France.

Why use ADMS-Urban Regional Model Link?

Nesting the local model ADMS-Urban within a regional model using the ADMS-Urban Regional Model Link allows both the resolution of high concentration gradients close to a source, and the accurate representation of transport and chemistry over larger spatial and temporal scales. The ADMS-Urban RML system combines the regional and local concentrations in such a way as to minimise double-counting of emissions, while remaining computationally efficient and user-friendly.

The principal features of the ADMS-Urban RML system are:

• A user-friendly graphical interface
• An automated control system with logging of progress to file and screen
• Integration with CERC’s Run Manager software for distributing ADMS-Urban runs across multiple machines
• Compatibility with CMAQ, CAMx, CHIMERE, EMEP4UK and WRF-Chem regional air pollution models, with potential for extension to other regional models
• Automatic division of a large nesting domain into separate runs for each regional model grid cell, with appropriate local meteorology from the WRF meso-scale model and background concentrations
• Flexibility regarding the size and shape of the nesting domain
• No requirement to re-run the regional air quality or meteorological models
• Inclusion of advanced modelling techniques for urban areas, such as street canyon and urban canopy flow field calculations, through the use of ADMS-Urban