Analysis of the influence of solar activity and atmospheric factors on 7Be air concentration by seasonal-trend decomposition

Publication date: November 2016
Source:Atmospheric Environment, Volume 145
Author(s): M.C. Bas, J. Ortiz, L. Ballesteros, S. Martorell
⁷Be air concentrations were measured at the Universitat Politècnica de Valencia campus (in the east of Spain) during the period 2007–2014. The mean values of monthly ⁷Be concentrations ranged from 2.65 to 8.11 mBq/m³, showing significant intra and interannual variability. A seasonal-trend decomposition methodology was applied to identify the trend-cycle, seasonal and irregular components of the ⁷Be time series. The decomposition model makes it possible to estimate the influence of solar activity and atmospheric factors on the independent components, in order to find the different sources of ⁷Be variability. The results show that solar activity is a factor with a high inverse influence on the trend-cycle pattern of ⁷Be variability. Solar radiation, temperature and relative humidity are positive influential factors on the seasonal ⁷Be variation with a regular pattern over the years. Finally, the irregular component presents a significant negative correlation with precipitation and wind speed parameters, which have an irregular behavior over the years and seasons.



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