JMAís Regional ATM Calculations for the WMO Technical Task Team on Meteorological Analyses for Fukushima Daiichi Nuclear Power Plant Accident

 

Kazuo Saito, Toshiki Shimbori, and Roland Draxler

 

J. Environ. Radioactivity, pp. 185-199, DOI:10.1016/j.jenvrad.2014.02.007

 

Abstract - The World Meteorological Organization (WMO) convened a small technical task team of experts to produce a set of meteorological analyses to drive atmospheric transport, dispersion and deposition models (ATDMs) for the United Nations Scientific Committee on the Effects of Atomic Radiation's assessment of the Fukushima Daiichi Nuclear Power Plant accident. The Japan Meteorological Agency (JMA) collaborated with the WMO task team as the regional meteorological center of the country concerned with the accident, and provided its operational 5 km resolution mesoscale (MESO) analysis and its 1 km resolution radar/rain gauge-analyzed precipitation (RAP) data. The JMAís mesoscale tracer transport model was modified to a regional ATDM for radionuclides (RATM), which included newly implemented algorithms for dry deposition, wet scavenging, and gravitational settling for light particles. Preliminary and revised calculations of the JMA-RATM were conducted according to the task teamís protocol. Verification against 137Cs deposition measurements and observed air concentration time series showed that the performance of RATM with MESO data was significantly improved by the revisions to the model. The use of RAP data improved the 137Cs deposition pattern but not the time series of air concentrations at Tokai-mura compared with calculations just using the MESO data.

 

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