Led by: Humphrey Lean and Adrian Hill, Met Office

The meteorological wind and mixing within the urban environment play a key role in air quality as it influences factors such as chemical reactions and residence time (how long pollution remains in an area). The Met Office regional model development team is focused on the challenge of representing the complex diversity of the urban environment on many scales, down to the smallest street scales, in atmospheric models. This will consider the representation of turbulence and other processes in very high-resolution atmospheric models and also the development of methods to represent the urban surface. A key aspect of this work in relation to air quality is how transport and turbulent mixing are captured by these models. Firstly, there will be development of the Met Office’s existing 300m model of London, which runs routinely, and secondly the work will involve running research models of London at much finer grid lengths down to 25m. This work links with wider collaborative urban and high-resolution meteorological research activities being undertaken by the Met Office team based at Reading University. In conjunction with the high-resolution atmosphere-aerosol modelling and high-resolution full air quality modelling activities also taking place within the Clean Air programme, this theme is contributing to the eventual aim of a 100m scale coupled atmosphere-air quality model.

In addition, aerosol in the atmosphere is highly complex and dependent on a range of atmospheric processes. Work to study this is led by the Atmospheric Processes and Parameterisations group, looking to improve the modularity of the UKCA-mode aerosol scheme and develop capability and understanding of critical aspects of how high resolution meteorological-aerosol modelling performs. This work will also make use of the Met Office London model (300m grid length) and builds on existing aerosol, microphysics and high-resolution Numerical Weather Prediction (NWP) work underway at the Met Office, supporting the future UK air quality forecast system.