title: Ensemble-based simultaneous emission estimates and improved forecast of radioactive pollution from nuclear power plant accidents: application to ETEX tracer experiment.
abstract: The accidental release of radioactive materials from nuclear power plant leads to radioactive pollution. We apply an augmented ensemble Kalman filter (EnKF) with a chemical transport model to jointly estimate the emissions of Perfluoromethylcyclohexane (PMCH), a tracer substitute for radionuclides, from a point source during the European Tracer Experiment, and to improve the forecast of its dispersion downwind. We perturb wind fields to account for meteorological uncertainties. We expand the state vector of PMCH concentrations through continuously adding an a priori emission rate for each succeeding assimilation cycle. We adopt a time-correlated red noise to simulate the temporal emission fluctuation. The improved EnKF system rapidly updates (and reduces) the excessively large initial first-guess emissions, thereby significantly improves subsequent forecasts (r = 0.83, p < 0.001). It retrieves 94% of the total PMCH released and substantially reduces transport error (>80% average reduction of the normalized mean square error).
authors: Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing, PR China; Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA. Electronic address: zhangxiaole10@mails.tsinghua.edu.cn.
authors: X L
authors: XL
authors: Zhang
authors: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA.
authors: Q B
authors: QB
authors: Li
authors: Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing, PR China.
authors: G F
authors: GF
authors: Su
authors: School of Mechatronics Engineering, Beijing Institute of Technology, Beijing, PR China.
authors: M Q
authors: MQ
authors: Yuan
mesh_terms: D008956:Models, Chemical; D055848:Nuclear Power Plants; D011834:Radiation Monitoring / Q000379:methods*; D018788:Radioactive Hazard Release; D011848:Radioactive Pollutants / Q000032:analysis*; D011849:Radioactive Tracers; D011850:Radioactive Waste / Q000032:analysis*
chemical_list: D011848:Radioactive Pollutants; D011849:Radioactive Tracers; D011850:Radioactive Waste
keywords: Augmented ensemble Kalman filter; Emission estimate; European Tracer Experiment; Improve dispersion forecast; Nuclear power plant accident