Abstract
The variation in the 14C concentration with time has been experimentally studied both in the upper atomosphere (at an altitude of about 10.6 km above sea level) and on the ground at various localities since 1964. During the first several years, the activity of 14C in the upper troposphere was lower than that in the lower stratosphere but higher than that at the localities on the ground. But, the difference in the 14C activity among the lower stratosphere, the upper troposphere and the localities on the ground as well as in the 14C concentration has decreased with time. The samples in the upper atomosphere have been classified by the Siberian and Ogasawara air masses which are originated in the polar continental zones(Pc) and in the subtropical zones(Tm), respectively. At first, the 14C concentration in the Siberian air mass was higher than that of the Ogasawara air mass and decreased more rapidly than that of the Ogasawara air mass. In 1965, the 14C concentration in both air masses became the same value and then the concentration in the Ogasawara air mass seems to become much higher. The variation in the 14C concentration with time at the localities on the ground has been compared with the report of United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and our results show slightly lower 14C activity than that of the UNSCEAR report.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
