Long-range atmospheric transport Beryllium-7 to region the Sea of Japan

Abstract

Concentrations of cosmogenic beryllium-7(7Be) and atmospheric aerosols were measured in the atmosphere of the coastal zone of Vladivostok in 2013–2014. The 7Be concentrations ranged from 0.5 to 4.1 mBq/m3, with the lowest values in summer and the highest in spring and autumn; the mean value was 2.2 mBq/m3. Analysis of meteorological data in the synoptic scale showed an inverse correlation with wet deposition rates R = −0.55 (p = 0.0001) and H2O mixing ratio R = −0.49 (p = 0.0001) and a positive with an average maximum height of 120-h backward trajectories of air masses R = 0.65 (p = 0.0001). Angular cluster analysis showed the 7Be concentration to be dependent on the north-western (R = 0.53, p = 0.001) and eastern winds (R = −0.7, p = 0.0001 for 2013 and R = −0.49, p = 0.002 for 2014). The multiple regression analysis identified five factors in 7Be concentration: altitudes (b = 0.44), air temperature (b = 0.36), a portion of trajectories in the pacific (North-East direction) cluster (b = −0.32), aerosol concentrations (b = 0.28) and wet precipitation rates (b = −0.24). The model has a good correlation with the data (adjusted R2 = 0.55). It was found that the direction and height of the air masses trajectories in the lower troposphere strongly influence the concentration of 7Be.