Description
Releases of hazardous materials into atmosphere can arise from natural phenomena (volcanic ash release) or human activity (nuclear accidents or chemical releases). The amount of material released and the time evolution of the release (the so-called source term) is often not known, although this determines both the severity and the location of its impact. The overall objective of this project is to develop methods for determining the source term of an accidental release of hazardous substances into the atmosphere which is suitable for both real-time application (e.g., for emergency preparedness) and assessment of environmental damages. The team combines expertise of Norwegian partner on atmospheric modeling and expertise of the Czech partner on statistical inverse modeling. The resulting models and algorithms will be publicly available and the project members will assists with their transfer to national and international organizations such as radiation protection authorities (Czech, German and UN), the Volcanic ash committee and potentially other environmental authorities.
Summary of project results
Releases of hazardous materials into the atmosphere can arise from natural phenomena (e.g. volcanic ash release) or human activity (e.g. nuclear accidents or chemical releases). The amount of material released and the time evolution of the release (the so-called source term) is often not known, although this determines both the severity and the location of its impact. The overall objective of this project was to develop methods for determining the source term of an accidental release of hazardous substances into the atmosphere, which are suitable for both real-time application (e.g., for emergency preparedness) and assessment of environmental damages. The team combined expertise of the Norwegian partner on atmospheric modeling and expertise of the Czech partner on statistical inverse modeling. This complementary expertise allowed applying more advanced inverse modeling techniques in the challenging domain of inverse atmospheric modeling. Both institutions benefited from the partnership by gaining knowledge and experience in the complementary domain. From the beginning of the project we have developed new inversion methods for source term determination. The new methods require less manual interaction and tuning and more natural parameterization. Hence, they are suitable for automatic determination of the source term in practice. The resulting algorithms are expected to be more accurate and thus provide better support for decision-making authorities in the field of atmospheric pollution. We collected data sets of the Chernobyl and Fukushima nuclear accidents and of the accidental release of radioactive iodine in central Europe in 2011. Collecting Chernobyl data resulted in a data rescue activity, as it turned out that most of the originally measured data are not available anymore. We have made all identified data publicly available. At the example of the above data sets and data from a tracer experiment, we demonstrated the performance of our algorithms. We are in contact with national and international organizations such as radiation protection authorities (Czech, German and UN). Our work has been published in 6 peer-reviewed journal papers and four other papers are in review process.
Summary of bilateral results
The beneficiaries were developing inverse modelling. The main benefit of the beneficiary is the latest forward model developed by the project partner and the provided training. The donor partner got access to inverse methods that are normally not used in the atmospheric sciences. The project partner provided the latest versions of the dispersion model FLEXPART, data on tracer experiments, state of the art inversion tools and experience with publication in high quality journals. The partnership provided unique combination of expertise in atmospheric dispersion modelling of NILU with expertise in inverse modelling methods of UTIA. Complementarity of the skills of the partners has been confirmed and we plan to continue working on similar scientific issues in the future. The methods developed in this project were provided to the radiation protection authorities and the general public. Their use in future accidents can improve public protection measures.