LAUSR

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.