USE OF BE-10 IN POLAR ICE TO TRACE THE 11-YEAR CYCLE OF SOLAR-ACTIVITY

A DETAILED knowledge of the history of solar magnetic activity is important in several respects. From satellite data there is increasing evidence that solar magnetic activity and solar irradiance are positively correlated, a conclusion with important implications for climatology1. Because of the complexity of variations in solar activity, a long record is necessary for understanding the mechanisms responsible for heliomagnetic cyclicity2. Here we show that 10Be concentrations in polar ice can be used to study variations in the solar activity - particularly the 11-year cycle - in time periods pre-dating historical records. © 1990 Nature Publishing Group.