Use of Be-10 in polar ice to trace the 11-year cycle of solar activity

It is shown here that Be-10 concentrations in polar ice can be used to study variations in the solar activity in time periods predating historical records, especially the 11-year cycle. Results for the period 1783-1985 are shown which demonstrate an anticorrelation between Be-10 and the sunspot number. This finding opens up the possibility of studying the long- term behavior of solar activity and the history of solar-terrestrial relationships. (C.D.)