Seasonal 7Be concentrations in near-surface air of Granada (Spain) in the period 1993-2001

Near-surface air samples for assessment of seasonal Be-7 levels were taken weekly at Granada, Spain, (37degrees10'50"N3degrees35'44"W, altitude 670m) in the period 1993-2001. The 7Be levels measured reflect strong seasonal trends. Concentrations during autumn and/or winter showed a minimum (ca. 1.5 mBq/m(3)), and in each year a fallout maximum was found in summer (ca. 7.6mBq/m(3)). Multiple regression of Be-7 concentrations with temperature and rainfall, and with sunspot number explained. about 71% of the variance in the Be-7 data. The data reveal strong variations in the mean annual Be-7 concentrations due to variations in the flux of cosmic galactic primary radiation caused by the 11-year sunspot cycle. A difference of a factor of 2.6 was found between the highest level (5.8 mBq/m(3)) obtained in 1996 (beginning of the solar cycle 23) and the lowest (2.6 mBq/m(3)) obtained in 2000 (maximum of the solar cycle 23) (C) 2003 Elsevier Ltd. All rights reserved.