7 Be atmospheric concentration in Panama City: influence of climatic conditions and atmospheric recovery process

Abstract

The daily distribution of 7Be surface air concentration shows a right-skewed pattern, with a mean of 2.37 ± 1.47 mBq m−3 (AM ± SD) and a geometric mean of 1.88 mBq m−3 and a CV of 62 %. Principal componentanalysis (PCA) revealed positive correlations between 7Be surface air concentration with temperature and wind speed and negative with precipitation and month of the year. Rainfall significantly affects 7Be content and masks the impact of other variables on them. Precipitation under 1 mm reduces 7Be in air by 1.5 times, with increasing amounts having a greater effect. Rain duration and intensity impact remaining 7Be levels, with longer and lighter rains more effective at removal. When the influence of the rains is excluded, the ⁷Be surface air concentration correlates positively barometric pressure and negatively with sunspot numbers. Additionally, it is observed that relative humidity values above 60% significantly decrease ⁷Be in the air. A seasonal pattern in 7Be surface air concentration is evident, with peaks during dry and warm months. In March, the mean concentration is 3.4 times higher than in September. This pattern results from various factors showing seasonal behaviour. During dry months, increased temperature, barometric pressure, and wind speed contribute to higher 7Be content. In contrast, during rainy months, precipitation and high relative humidity act as key factors in reducing 7Be levels in surface air. And for this region, the horizontal influx of beryllium-rich air masses plays a larger role in the 7Be surface air concentration than the vertical influx from higher atmospheric layers. Rainfall is the primary cause of the decrease in 7Be surface air concentration. Following rainfall, the atmosphere gradually is restored in 7Be content, following a saturation curve, with reload coefficient of 0.36 ± 0.05 d−1 and a recharge time of 2.8 ± 0.2 d.