Simulation of atmospheric transport of caesium-137 from the Fukushima-Daiichi nuclear power plant over the Pacific Ocean
Résumé
This animation shows the dispersion of the caesium-137 radioactive plume from the Fukushima-Daichii power plant over Japan, the Pacific Ocean and the West coast of North America. It depicts the activity concentration of this radionuclide at ground level. The unit is Becquerel per cubic meter. It has been simulated using the 3D numerical model Polyphemus/Polair3D which accounts for several processes such as advection by the wind, turbulent diffusion, as well as dry and wet deposition. The meteorological fields that drive this transport model simulation are from the ECMWF at a resolution of 0.25°x0.25°. The source term for the emission of caesium-137 at the power plant which is used in this simulation has been estimated by inverse modelling in Winiarek et al. 2014, as a result of a collaboration between École des Ponts ParisTech and the Institute for Nuclear Radioprotection and Safety (see references below). One must be cautious in interpreting the values since this type of simulation remains impacted by high uncertainty in the source term, in the modelling of the physical process and to a lower degree by the meteorological fields.
