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

Atmosphere

Masaru Kunii¹  TsuyoshiThomas Sekiyama²  Mizuo Kajino² 

[1] Japan Meteorological Agency, Tokyo 1058431, Japan;Meteorological Research Institute, Tsukuba 3050052, Japan;

关键词: probabilistic simulation;    plume dispersion;    data assimilation;    ensemble spread;    Fukushima nuclear accident;    radioactive cesium;   

DOI  :  10.3390/atmos12060662

来源: DOAJ

【 摘 要 】

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

【 授权许可】

Unknown