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

本研究的目的是建立包括放射性物质在内的大气污染物远距离传输的数值模拟模型。建立了天然存在的放射性稀有气体氡-222的数值模拟模型。在名古屋附近的一个局地尺度（80kmX80km）模拟模型和东亚地区的一个区域尺度（4000 kmx4000 km）模拟模型组成了该模型。为了将计算结果与测量结果进行比较，在名古屋、金泽和福井对大气氡进行了连续测量。每四个季节的计算结果与名古屋的测量结果相当吻合。在目前的工作中，我们也开始开发一个动态模型来更好地模拟氡的输运。本文所建立的区域尺度模式已应用于东亚地区水汽中氚的远距离输运的模拟。1978年11月，在日本氚浓度远高于目前低水平的情况下，用两周左右的时间计算了氚的输运量，而中国关于环境氚的文献也比较丰富。计算结果与观测结果在两倍以内一致。因此，本研究为氚的长距离输运提供了初步的模拟模型，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.