WSEAS Transactions on Environment and Development
Print ISSN: 1790-5079, E-ISSN: 2224-3496
Volume 11, 2015
Description and Validation of a Numerical Box Model for Near-Surface Atmospheric Radon
Authors: ,
Abstract: A numerical box model has been developed to better understand the physical drivers of the diurnal and seasonal variability of Radon-222 in the atmospheric boundary layer and to assess the role of different mechanisms controlling the tracer abundance immediately above the Earth surface. Dynamical removal due to turbulent convective motions is found to be the dominant controlling process. Since the latter is highly dependent on atmospheric meteorological conditions, a realistic representation of the small-scale convective mixing term in the mass continuity equation has been obtained by constraining the box model with meteorological parameters collected in a radon measurement site, located in the town of L’Aquila in central Italy. Model results are finally validated by direct comparison with hourly observations of radon taken in this site: a correlation coefficient of 0.8 is found between measured and modelled radon hourly values over two years of data. It is also shown how the model can be used to infer to the magnitude of the monthly averaged radon soil flux in the L’Aquila measurement site. Radon data collected during March 2009 have also been analysed to find possible signs of perturbation due to the on-going seismic activity that would have reached its peak in the April 6th, 2009 destructive earthquake. No significant radon activity increase was observed in L’Aquila at that time with respect to a previous ‘seismically-unperturbed’ year, during the same month with similar meteorological conditions, nor any statistically significant increase (or change) of the model derived radon soil flux.
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Keywords: Box model, Mass continuity equation, Meteorology, Atmospheric boundary layer dynamics and transport, Atmospheric Radon
Pages: 126-135
WSEAS Transactions on Environment and Development, ISSN / E-ISSN: 1790-5079 / 2224-3496, Volume 11, 2015, Art. #14