Seasonal variations of anthropogenic radiocarbon in the atmosphere

Seasonal 14C variations in atmospheric CO2 caused by nuclear bomb tests and by fossil-fuel combustion are discussed. The investigated time interval is from 1968 to 1980. A comparison of Bratislava and Tbilisi 14C data shows that both are influenced by the Suess effect. Summer-winter 14C variations observed in these data are predominantly due to the fossil-fuel CO2 increase during winter months. A strong correlation between the 14C concentration and the temperature during a year has been found. In contrast to the 14C variations in CO2 from urban areas the clean air 14C data have shown that the bomb effect is responsible for the seasonal 14C variations in non-industrialized areas.