Seasonal variations in the concentration of 10Be, Cl-, NO3-, SO42-, H2O2, 210Pb, 3H, mineral dust, and σ18O in Greenland snow

A detailed snow pit study at Dye 3, South Greenland, has been carried out in order to investigate the seasonal variations of 10Be, Cl−, NO3−, SO42−, H2O2, 210Pb, 3H, Mn and σ18O. Special emphasis was placed on understanding the causes of 10Be variations because this isotope can be used to trace the history of solar activity. A sampling interval of 5 cm was chosen to assure a mean time resolution of about 20 samples per year for the period 1978–1983. Four different categories of seasonal variations were identified: strong summer peaks (σ18O, H2O2, 3H), weak bimodal peaks (NO3−, SO42−, conductivity, 10Be), a fall peak (210Pb) and a winter-spring peak (Cl−, Mn). Although we are still far from a detailed understanding of the mechanisms which control the measured compositions, there are indications that different processes dominate at different seasons. NO3−, SO42−, Mn and Cl− variations suggest that aerosol transport is most important during winter-spring. In summer-fall there seems to exist a second period of long range transport from low latitude continental areas resulting in enhanced concentrations of 210Pb, 10Be and SO42−