Ensemble Dispersion Simulation of a Point-Source Radioactive Aerosol Using Perturbed Meteorological Fields over Eastern Japan

We conducted single-model initial-perturbed ensemble simulations to quantify uncertainty in aerosol dispersion modeling, focusing on a point-source radioactive emitted from the Fukushima Daiichi Nuclear Power Plant (FDNPP) March 2011. The ensembles of meteorological variables were prepared using data assimilation system that consisted non-hydrostatic weather-forecast model with 3-km horizontal resolution and four-dimensional local transform Kalman filter (4D-LETKF) 20 members. emission was not perturbed. weather validated in-situ measurements at Hitachi Tokai, respectively, approximately 100 km south FDNPP. provided probabilistic information multiple case scenarios for plumes. Some members successfully reproduced arrival time intensity plumes, even when deterministic simulation failed reproduce them. found small spread wind speed produced large uncertainties concentrations.