资源环境科技发展态势分析平台

Several aspects concerning the origin and nature of grand solar minima remain unclear, and more high-resolution Be-10 and C-14 records are needed to improve our understanding of these phenomena. Here, we report 137 new high-precision, annually resolved radiocarbon concentrations based on oak from the Danish dendrochronology. The new record covers a period (CE 1432-1578) that encompasses most of the penultimate grand solar minima known as the Sporer Minimum. A detailed comparison between the Sporer and Maunder (CE 1640-1720) minima shows that the Sporer Minimum is associated with enhanced Delta C-14 variability in a band centered around the 11-year Schwabe cycle from CE 1450 to 1479 and between CE 1545 and 1578, whereas little 11-year variability is observed from CE 1479 to 1539. In contrast, we only observe enhanced 11-year variability after the end of the Maunder Minimum at CE 1722-1744, which could indicate that the nature and origin of the two minima were different.