RADIOACTIVE FALLOUT IN JAPAN AND ITS BEARINGS ON METEOROLOGICAL CONDITIONS

The relation between radioactive fall-out and meteorological conditions was studied. The relation of rainfall amount to fall-out (R) can be expressed fairly well by the formula R= C (1 -- e/sup - beta P/ + /sub K/P), where P is the amount of rainfall, C is the air activity, beta and k are constants. There is little correlation between the surface weather conditions and fall-out while a considerably higher correlation was found among a trough at 500 mb, position of jet stream. and air activity. The activity increases remarkably when a trough at 500 mb passes above and a core of the jet stream is located above or a little south or an observation point. The analytical results of studies of Sr/sup 90/ deposition in Japan since 1954 and its seasonal variation are also discussed. (auth)