In collaboration with the Royal Meteorological Institute and the CTBTO the dispersion model FLEXPART with Numerical Weather Prediction input from the ECMWF at a global scale and a horizontal resolution of 0.5 degrees will be further made operational to perform the necessary calculations for the uncertainty quantification.
A study will be made on the sensitivity of the model results as a function of model parameters over the realistic physical range. In this way most important factors influencing the model uncertainty will be identified.
In order to assess the uncertainty of changing weather conditions on the modelling dispersion results, FLEXPART will to be set-up to run with the 50 members of the ECMWF Ensemble Prediction System (EPS), which are intelligently designed to take into account uncertainty in numerical weather forecast. This will make it possible to assess for each species under consideration an uncertainty analysis.
To use this uncertainty information in an operational context, an algorithm will be designed to incorporate this NWP uncertainty for the species under consideration in the operational model which only uses the deterministic ECMWF input, since it is computationally very expensive to run the dispersion model ingesting the 50 EPS members into FLEXPART.
To contribute to the identification of the most important sources of uncertainty and to determine in the end the relevance of the uncertainty quantification one or more cases will be analyzed. These cases can include the North-Korean nuclear bomb tests, the Fukushima nuclear accident and releases from radiopharmaceutical facilities in normal operation. For all of these cases high quality data from the radionuclide component (including noble gas component) of the International Monitoring System can be used.