FRACTAL DIMENSIONS OF THE OUTDOOR RADON ISOTOPES TIME-SERIES

The fractal properties of the Rn-222/Rn-220 time series were studied u sing Hurst's rescaled range analysis, as well as the box counting meth od. The values of the fractal dimensions show that Rn-222 and Rn-220 c an be considered as tracers of a dynamic system whose physical variabl es continuously interact, some of them in a chaotic; but also determin istic manner. The determined values of Hurst's coefficients (0.809 for Rn-222 and 0.896 for Rn-220) highlight a persistent behaviour of both gases and their decay products. These values characterize the overdif fusive media in which the radon atoms and the aerosol particles in the air undergo turbulent diffusion. Copyright (C) 1996 Elsevier Science Ltd.