Published recommendations for use of NWP meteorological data in dispersion modelling

CERC`s investigation of the impacts of using modelled (NWP) meteorological data on dispersion modelling outcomes has now been published by the Atmospheric Dispersion Modelling Liaison Committee (ADMLC). The project was commissioned to examine the effects of NWP model grid resolution on dispersion modelling, in both regulatory and emergency planning contexts, and to make recommendations for the use of NWP data in dispersion modelling.

The report begins with an evaluation of NWP outputs in comparison with meteorological observations at eight UK sites (shown on the map). This is followed by a comparison of ADMS and AERMOD dispersion outcomes for idealised sources at four locations with observed and modelled meteorological data. The report also includes an investigation of the interaction between fine-scale NWP data and local flowfield modelling using the FLOWSTAR model for flow over complex terrain in ADMS. Finally, there are results from the UK Health Security Agency (UKHSA) investigation of the effects of NWP grid resolution on the outcomes of probabilistic accident consequence modelling with the PACE model.

Interim results from the project were presented at CERC`s ADMS User Group Meetings in 2022 and 2023; the presentations are available from the User Area. Christina Hood from CERC will also present the sensitivity of ADMS and AERMOD dispersion outputs to varying input meteorological data at the international conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes (Harmo) in June 2024.