One year of 222Rn concentration in the atmospheric surface layer

[摘要] A one-year time series of ²²²Rn measured in a rural area in the Northof Italy in 1997 is analyzed. The scope of the investigation is to betterunderstand the behavior of this common atmospheric tracer in relation to themeteorological conditions at the release site. Wavelet analysis is used asone of the investigation tools of the time series. The measurements andscalograms of ²²²Rn are compared to those of wind-speed, pressure,relative humidity, temperature and NO_x. The use of wavelet analysisallows the identification of the various scales controlling the influence ofthe meteorological variables on ²²²Rn dispersion in the surface layerthat are not visible through classical Fourier analysis or direct timeseries inspection. The analysis of the time series has identified specificperiods during which the usual diurnal variation of radon is superimposed toa linear growth thus indicating the build up of concentration at themeasurement level. From these specific cases an estimate of the surface fluxof ²²²Rn is made. By means of a simple model these special cases arereproduced.

[学科分类] 大气科学