Uncertainty quantification of atmospheric transport modelling of radioxenon concentrations in Europe from regional civil sources

Radioxenon monitoring by the International Monitoring Station (IMS) is a key component of the verification of the CTBT. Atmospheric transport modelling can be used to determine the sources of radioxenon plumes and predict the future evolution of plumes. However, ATM simulations are prone to errors that are difficult to quantify. Therefore, besides the outcome of ATM simulations, an accurate uncertainty quantification is also important for decision makers. Here we assess the capability of predicting the radioxenon background in Europe from regional sources, together with the uncertainty of the dispersion simulation by using meteorological ensembles. The FLEXPART model is used with meteorological data from a subset of the ensemble prediction system of the European Centre for Medium-Range Weather Forecasts. Results from the FLEXPART dispersion model will be presented and validated with radioxenon measurements from the IMS for a full year. The added value of the ensemble will be discussed