Os Mecanismos de Difusão e Transporte Convectivo na Formação de Anomalias Superficiais do Radônio-222 gerado em Profundidade

Abstract

A preliminary study on the importance of a thermally-activated convective transport of radon is made in order to explain radon anomalies at surface generated at great depth. It is theoretically shown that convective currents should be of the order of 10 ¡rm/s or larger to explain such anomalies. The influence of surface temperature changes on the convective transport is also discussed. Seasonal changes in temperature typical of climates such as that of southern Brazil can develop thermal inversion layers at depths up to 20 metres. The optimum period of the year for the employment of surface emanometric techniques is during the second and the third months after the winter peak when the thermal inversion barriers are less intense.