Solar Activity during the Maunder Minimum: Comparison with the Dalton Minimum

The solar modulation potential has been reconstructed from data on the 10Be concentration in south and central Greenland ice over more than 500 last years. These two reconstructions, along with fourteen others obtained by various authors from data on the cosmogenic isotopes 14C and 10Be, have been investigated in the time interval 1630–1840 encompassing the Maunder and Dalton minima. The information contained in these sixteen paleoreconstructions has been generalized. The available data on the concentration of cosmogenic isotopes in terrestrial archives suggest that the solar activity in the first part of theMaunder minimum (1645–1680) was lower than that at the Dalton minimum (1792–1827), while in the second part (1680–1715) it was considerably lower. At the same time, at the beginning of theMaunder minimum (1645–1660) the solar activity could reach levels exceeding noticeably the estimates based on telescopic observations. Possible causes of these discrepancies and the directions of further research are discussed.