Seasonal evolution of 7,10Be and 22Na in the near surface atmosphere of Cáceres (Spain)

Publication date: February 2019

Source: Journal of Environmental Radioactivity, Volume 197

Author(s): A. Rodríguez-Perulero, A. Baeza, J. Guillén

Abstract

Cosmogenic radionuclides provide information about air masses exchanges between stratosphere and troposphere. The ⁷Be concentration in aerosols usually shows a seasonal variability, depending also of the climatic conditions. There are, however, fewer data available of the behavior of other cosmogenic radionuclides, such as ¹⁰Be and ²²Na. In this work about 7 years of aerosols collected in Cáceres (Spain) were analyzed. The ⁷Be concentration was higher than ²²Na and ¹⁰Be, being the ²²Na/⁷Be and ¹⁰Be/⁷Be ratios (1.16 ± 0.02)·10⁻⁴ and (1.5 ± 0.3)·10⁻⁴ respectively. For the ²²Na/⁷Be, a seasonal variation was observed, being higher in spring/summer. Seasonal variation of ⁷Be and ²²Na were explained using a model taking into account local values of the solar radiation, rainfall and dry deposition. The effective residence time for ⁷Be and ²²Na were (9.9 ± 1.0) and (11.3 ± 1.4) d respectively. Both ⁷Be and ²²Na seemed to decrease with increasing number of sunspots, although it was not statistically significant probably due to the low solar activity reported in the analyzed period.

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