The Fourier analysis applied to the relationship between 7Be activity in the Serbian atmosphere and meteorological parameters

Abstract

Air sample monitoring in Serbia, Belgrade started in the 1960s, while 7Be activity in air and total (dry and wet) deposition has been monitored for the last 22 years by the Environment and Radiation Protection Department of the Institute for Nuclear Sciences, Vinca. Using this data collection, the changes of the 7Be activity in the air and the total (wet and dry) deposition samples, as well as their correlation with meteorological parameters (temperature, pressure, cloudiness, sunshine duration, precipitation and humidity) that affect 7Be concentration in the atmosphere, were mathematically described using the Fourier analysis. Fourier analysis confirmed the expected; the frequency with the largest intensity in the harmonic spectra of the 7Be activity corresponds to a period of 1 year, the same as the largest intensity frequency in Fourier series of meteorological parameters. To analyze the quality of the results produced by the Fourier analysis, we compared the measured values of the parameters with the values calculated according to the Fourier series. Absolute deviations between measured and predicted mean monthly values are in range from 0.02 mBq/m3 to 0.7 mBq/m3 for 7Be activity in air, and 0.01 Bq/m2 and 0.6 Bq/m2 for 7Be activity in deposition samples. Relatively good agreement of measured and predicted results offers the possibility of prediction of the 7Be activity.