Development of a Prediction Method for Regional Scale Air Pollution - By Means of Numerical Simulation of Atmospheric Diffusion of Natural Radioactivity -

本研究的目的是开发一个包括放射性物质在内的大气污染物远程传输的数值模拟模型。建立了天然放射性稀有气体氡-222的数值模拟模型。以名古屋为中心的局地尺度(80公里×80公里)模拟模式和东亚地区尺度(4,000公里×4,000公里)的模拟模式构成了该模式。为了比较计算结果和测量结果，在名古屋、金泽和福井进行了大气氡的连续测量。四个季节的计算结果与名古屋的实测值吻合较好。在目前的工作中，我们还开发了一个动力学模式来更好地模拟氡的输运。目前的区域尺度模式已经应用于东亚地区水汽中氚的远程输运的模拟。1978年11月，日本的氚浓度远高于目前的低水平，中国有大量的环境氚文献，计算了大约两周的氚输运。计算结果与实测值相差不超过2倍。因此，本研究为氚的远程传输提供了初步的阶段模拟模型，但仍有许多问题有待解决。

The purpose of the present research is the development of a numerical simulation model for long range transport of atmospheric pollutants including radioactive substances. A numerical simulation model has been constructed for naturally occurring radioactive rare gas, radon-222. A local-scale (80kmX80km) simulation model around Nagoya and a regional-scale one (4,000kmX4,000km) over eastern Asia compose the model. To compare calculational results with measurements, continuous measurements of atmospheric radon have been carried out at Nagoya, Kanazawa and Fukui. The results of calculation in each four season coincided fairly well with measured one at Nagoya. In the present work, we have also started to develop a dynamic model to simulate better the transport of radon.The present regional-scale model has been applied to the simulation of long-range transport of tritium in water vapor over eastern Asia. The transport of tritium was calculated for about two weeks in November, 1978, when the tritium concentration in Japan was much higher than the low level at present and there are abundant literature of environmental tritium in China. The calculated results agreed within the factor of two with the observed one. Thus the present research have provided a preliminary stage simulation model for long range transport of tritium, but there are many problems to be solved in the future.