Results of atmospheric radioactivity observations in 1983

The results of radioactivity observations in the atmosphere and in sea water made by Japan Meteorological Agency in the year 1983 throughout Japan are given in tables and also the sampling and measuring methods. Radioactivity measurements are made at 18 land stations and at five marine-observatories-operating research ships. Collected samples are sent regularly to Geochemical Laboratory in JMA's Meteorological Research Institute for identification and measurement of specified species. Contents are the following: gross beta radioactivity in precipitation, gross beta radioactivity in airborne dust, monthly mean 90Sr concentration in airborne dust, annual mean 90Sr concentration in airborne dust, gross beta radioactivities in precipitation and airborne dust (summary), gross beta radioactivity in sea water, monthly deposition of 90Sr, monthly deposition of 90Sr and 137Cs, etc., at MRI, annual deposition of 137Cs and 90Sr, natural background radioactivity, and vertical distribution of radioactivity in free atmosphere. (Mori, K.)