Investigating nuclear events and vector borne disease risk through atmospheric dispersion modelling with HYSPLIT

As a part of the Agricultural Meteorology research unit at Met Éireann, atmospheric dispersion modelling (ADM) is used to investigate and provide forecast for emergency and risk awareness networks. ADM is performed computationally to create mathematical simulations of the transport and dispersion of particles in the atmosphere. At present, Met Éireann uses the HYSPLIT  program in order to calculate and model the trajectory and concentrations of airborne pollutants. HYSPLIT allows for a high degree of customization of the pollutant source terms, which enables dispersion modelling estimations of emission from both man-made and natural sources of interest, including but not limited to nuclear release, smoke, small insects and pollen. This can be used to predict future concentrations, depositions and arrival times of particles under specific scenarios.

Met Éireann currently acts in support of the EPA for nuclear dispersion modelling, in the event of an emergency. We provide daily meteorological forecast data to the EPA and, as a part of the Response and Assistance Network (RANET), can provide additional modelling during an event if requested. We participated with the EPA during the ConvEx-3 exercise in 2025, simulating a nuclear emergency in Romania, to test our communication and dispersion modelling capabilities. Our communications during the event were responsive and modelling results across multiple programs agreed. The experience of the exercise will be used in the development of ensemble dispersion modelling pipelines for future events.

Met Éireann also runs an operational daily forecast of Bluetongue virus, which is based on dispersion modelling the possible transport of the insect that act as the vector. This is provided to relevant agricultural stakeholders, particularly in close collaboration with UCD and DAFM. As climate change continues, a range of pests and possible disease vectors that were either previously unknown to Ireland or inactive at certain times of the year could potentially harm native species of plants & animals. This may necessitate further research and expansion of the current dispersion work on forecasting possible pest or disease vector risks.