The IAQM and Atmospheric Dispersion Modelling Liaison Committee (ADMLC) are hosting a joint in-person seminar on the 18th October. 

Meteorological (met) station sites may be too far from, and situated in differing topography to, the release location(s) and thus met station derived data may be unrepresentative of a study area. The quality and availability of numerical weather prediction (NWP) model data is continuously improving. As a result, NWP model data is becoming more widely used as input to air dispersion modelling for regulatory air quality impact assessments, and for probabilistic accident consequence assessments in respect of radiological releases.

The resolution of NWP model data has been improving with the advances in predictive algorithms and computing power. For example, the Met Office Unified Model (UM) NWP data resolution was 60 km prior to 2004, then down to 12 km in 2004, 4 km in 2007 and 1.5 km in 2013. Similarly, data derived from other mesoscale models such as WRF and NEMS is commonly available at a range different resolutions, including from 1 km to 12 km, and coarser resolutions e.g. 31 km, from global models, for example, from Global Forecast System (GFS) and Integrated Forecast System (IFS) model, developed by the European Centre for Medium-Range Weather Forecasts (ECMWF).

Different NWP modelling approaches and spatial resolutions result in different degrees of representativeness of NWP met data at a local level. The effect of terrain on air flow may be considered in an NWP model, depending on the scale of terrain and NWP model resolution. Since some atmospheric dispersion models, e.g. ADMS, explicitly consider the impact of terrain effects on air flow, there is concern that double counting of the terrain effect for a regulatory air dispersion modelling assessment may occur.

Therefore the ADMLC funded an investigation into the consequence of using different spatial and temporal resolution of NWP met data on:

• (a) model predictions of annual mean concentration and high percentile hourly concentrations for a regulatory assessment.
• (b) model endpoints derived by way of probabilistic accident consequence assessments.

CERC and UKHSA worked collaboratively to address the needs of the ADMLC, producing a report which documents the study’s findings and recommendations.

Firstly, the seminar provides an opportunity for the authors to share these findings and recommendations. Secondly, the seminar provides an opportunity to discuss any potential issues raised in the context of the study. For example, are the recommendations likely to impact the application of meteorological data in assessments forming Environmental Permitting Regulations submissions (including in areas of complex terrain)?

If the topics summarised above are of interest to you and your employer, please join us for this seminar – your attendance and contributions would be very much welcomed.

Agenda

• 9:30am: Tea & Coffee
• 10.00am: Welcome/intro – ADMLC Chair
• 10.10am: Findings of ADMLC study – CERC
• 11.10am: Findings of ADMLC study – UKHSA
• 11.30am: Tea & Coffee
• 12.00pm: New IAQM guidelines & the application of met data – Kieran Laxen
• 12.15pm: Regulatory perspective – Matthew Bevington
• 12.30pm: Discussion (inc consultants’ application of met data & interpretation of the ADMLC study)
• 1.00pm: Sandwich lunch & informal discussion

Register to attend 

There is no fee to attend this seminar. However, you must register to attend. Please request attendance by contacting the ADMLC Secretariat at: admlc@ukhsa.gov.uk. To help in the planning of the seminar please register by Friday 4th October.