0493137 20240103220442.320180910235959.9 85057047981 000455586500026 10.1002/qj.3403 20 s. P cav_un_epca*02575290035-9009144717 (2018)2781-2797Wiley Multi-species source term estimation Inverse modeling Gamma dose rate Nuclear accident Nuclides ratios Covariance matrix Chernobyl accident cav_un_auth*0267768 Tichý Ondřej Adaptivní systémy Department of Adaptive Systems AS AS UTIA-B Department of Adaptive Systems Ústav teorie informace a automatizace AV ČR, v. v. i. cav_un_auth*0101207 Šmídl Václav Adaptivní systémy Department of Adaptive Systems AS AS UTIA-B Department of Adaptive Systems Ústav teorie informace a automatizace AV ČR, v. v. i. cav_un_auth*0228606 Hofman Radek Adaptivní systémy Department of Adaptive Systems AS AS UTIA-B Department of Adaptive Systems CZ Ústav teorie informace a automatizace AV ČR, v. v. i. cav_un_auth*0363740 Evangeliou N. NO http://library.utia.cas.cz/separaty/2018/AS/tichy-0493137.pdf cav_un_auth*0318110 7F14287 GA MŠk CZ Determination of a source term of an accidental release of radioactive material into the atmosphere is very important for evaluating emergency situations and their consequences. However, knowledge of the source term and its composition is typically vague and uncertain. One possible way to obtain the source term is inverse modeling in which an atmospheric transport model is combined with field measurements. The most accessible measurements are those from gamma dose rate (GDR) detectors. However, GDR measurements represent a sum of contribution from all nuclides from both plume and deposition which makes the problem particularly difficult. The same difficulty arises when the measurements can not distinguish contribution from another species in the release, such as nuclides attached to different particle sizes. We propose a Bayesian method for recovery of the source term from GDR measurements where a priori knowledge on ratios of different species is given in the form of bounds. This knowledge is incorporated into the model of covariance matrix of the source term. The Bayesian methodology allows to handle uncertain knowledge on the nuclide ratios as well as unknown temporal correlations of the source term. We evaluate and compare the proposed method with other state-of-the-art methods on a twin experiment of a non-stationary release of 16 nuclides from the Czech nuclear power plant Temelin being registered by the Austrian GDR monitoring network. Real-world validation of the approach is performed on the latest measurements of concentration and deposition of caesium-137 from the Chernobyl accident, where we estimate composition of the source term from different particle sizes (species). The estimated source term is in very good agreement with previously reported results and the calculated species ratios are supported by the available observations. WOS BB 10000 10100 10103 2019 4 4 A hod 4ah 20231122143400.6 http://hdl.handle.net/11104/0286998 cav_un_auth*0336787 Norwegian Institute for Air Research NILU NO 1 Department of Adaptive Systems UTIA-B 10509 METEOROLOGY & ATMOSPHERIC SCIENCES S 2 Article Meteorology Atmospheric Sciences METEOROLOGY&ATMOSPHERICSCIENCES 3.582 1.009 10.2 0.02384 1.518 18616 2.607 2.661 216 Q2 66.348 71.5 Q2 Q1 1.04 Q1 71.512 2018 Soubory v repozitáři: tichy-0493137.pdf 85057047981 SCOPUS PUBMED 000455586500026 WOS cav_un_epca*0257529 Quarterly Journal of the Royal Meteorological Society 0035-9009 1477-870X Roč. 144 č. 717 2018 2781 2797 Wiley