To estimate local meteorological condition by studying the behavior of atmospheric ~(222)Rn, we measure the time variation of the vertical profile of ~(222)Rn concentration in the lower atmospheric boundary layer. The measurements of ~(222)Rn vertical profile were continuously obtained simultaneously at the four locations, where two mountaintops have different elevation (h=150,520m) and our labolatory (h=30m) is sited at Shimane peninsula and Oki island lies in Japan Sea. A diurnal change is clearly shown in ~(222)Rn profiles at 30m and 150m high due to the temperature inversion layer in the surface layer through the nighttime. But this change is rarely shown in ~(222)Rn profile at 520m high. It is considered that the top of surface inversion layer could not reach on the mountaintop of 520m high. And then, these ~(222)Rn profiles are clearly different in the long term variation. It is definitely considered that the atmospheric stability depends on the altitude in the atmospheric boundary layer. ~(222)Rn concentration in Oki is lower value on the whole and it rarely shows a diurnal change and its magnitude is small and, Oki is a seagirt island. Consequently, we would regard ~(222)Rn concentration in Oki as the background level in this area.
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