[3Q06-09] Environmental Radioactivity 2

[3Q07] Characterizing Regional-Scale Temporal Evolution of Air Dose Rates

(4)Temporal Changes of Radiation Air Dose Rates in the Regional Scale around the Fukushima Daiichi Nuclear Power Plant

*Haruko Murakami Wainwright¹, Jinsong Chen¹, Boris Faybishenko¹, Akiyuki Seki², Kimiaki Saito² (1. Lawrence Berkeley National Laboratory, 2. Japan Atomic Energy Agency)

Keywords:Fukushima, air dose rates

This study visualizes and analyses the temporal variation and decay of radiation air dose rates in the Fukushima evacuation zone. We integrate various types of datasets, such as ground-based walk and car surveys, and airborne surveys, all of which have different scales, resolutions, spatial coverage, and accuracy. This method is based on geostatistics to represent spatial heterogeneous structures, and also on Bayesian hierarchical models to integrate multiscale, multitype datasets in a consistent manner. The Bayesian method allows us to quantify the uncertainty in the estimates, and to provide the confidence intervals that are critical for robust decision-making. The results have shown (1) the faster environmental decay of air dose rates in the urban areas, and (2) the effect of decontamination in each year.