RADON CHAOTIC REGIME IN THE ATMOSPHERE AND SOIL

Radon concentrations were continuously measured outdoors, in a basement and in soil. The readings were made every 10 minutes and the series of records were analyzed to extract phase-space dynamical information. The application of fractal methods allowed exploration of the chaotic nature of radon in the atmosphere and soil. The computed fractal dimensions, such as the Hurst exponent (H) from the rescaled-range analysis, Lyapunov exponent (λ) and attractor dimension, provided estimates of the degree of chaotic behaviour. The obtained low values of the Hurst exponent (0 < H < 0.5) indicate anti-persistent behaviour (non-random changes) of the series, but the positive values of λ have pointed out a great sensitivity to initial conditions and the deterministic chaos that appeared in the variations of the radon concentrations. The calculated fractal dimensions of attractors indicate strong influence of meteorological parameters on radon in the atmosphere and soil