The applicability of the method for solving the inverse problem of atmospheric transport using the extended Kalman filter was studied to restore the parameters of the accident release from the Chernobyl nuclear power plant on the basis of the exposure dose rate measurements made in Pripyat town from 26 to 29 April 1986. The daily radionuclide emission values and meteorological parameters were estimated in the initial period of the accident. It was obtained that the convergence of the method essentially depends on the quality of the initial data of the gamma dose rate measurements, as well as the choice of the initial values in the iterative calculation process using the Kalman filter method. It was shown that depending the accumulation of radioactive fallout on the earth surface during the period under consideration, the convergence of the standard Kalman filter method may deteriorate. A modification of the algorithm is proposed to improve the convergence with highly noisy data, which makes it possible to achieve convergence of the method with a large uncertainty in the initial estimation of the source parameters.
Keywords: Chernobyl accident, atmospheric transport modeling, exposure dose rate, emission source parameters reconstruction, Kalman filter.
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