Latitudinal distributions of activities in atmospheric aerosols, deposition fluxes, and soil inventories of 7Be in the East Asian monsoon zone

Abstract

Activities of atmospheric aerosols, bulk deposition fluxes, and undisturbed soil inventories of 7Be were investigated in China's East Asian monsoon zone at various latitudes ranging from 23.8°N to 43.5°N. The annual latitudinal distributions of 7Be concentrations in aerosols follow a distribution pattern which looks similar to a normal distribution with the maxima occurring in the mid-latitude region. Simultaneous measurements of 7Be at various latitudes suggest that atmospheric circulation may play an important role in the latitudinal distributions of 7Be in surface air. Latitude and wet precipitation are the main factors controlling the bulk 7Be depositional fluxes. Significant seasonal variations in 7Be depositional fluxes in Beijing, a mid-latitude city, were observed with the highest flux in summer and the lowest in winter, whereas less seasonality were found in the high- and the low-latitude cities. The highest 7Be inventory in undisturbed soils in summer also occurred at a mid-latitudinal area in the East Asian monsoon zone. Precipitation is the main factor controlling the 7Be soil inventory in Qingdao with the highest values occurring in autumn followed by summer.