Features of seasonal dynamics of radon isotopes in surface atmosphere

Features of seasonal dynamics of radon isotopes and their decay products were investigated for Siberian (Russian Federation) climatic conditions. The analysis of results revealed a specific in the seasonal dynamics of radon: the maximum value is observed in winter, and the minimum—in spring. A completely different behavior was revealed for thoron. Minimal values are observed in winter and maximal values—in the warm period of the year. It was found that the presence and characteristics of snow cover greatly influence the seasonal variations in thoron volume activity. Precipitation has a significant impact on the seasonal dynamics of the radon decay products volumetric activity. Atmospheric turbulence strongly influences the daily dynamics of all the characteristics of the radon field. It was observed that diurnal variations of radon and thoron volumetric activity are clearly expressed during periods without rain or snow. The maximum of radon volumetric activity is observed in the pre-dawn hours, and the minimum—in the daytime. Moreover, diurnal variations of radon in the winter are characterized by a morning maximum of 8-9 o'clock, which is 1-2 hours later compared to the summer period.