[M-ZZ43] Transdisciplinary Network linking Space-Earth Environmental Science with History and Archaeology

[MZZ43-P07] Archival Investigations for Four Centuries of the Past Solar Cycle: A Progress Report

Hisashi Hayakawa^1,2, Kentaro Hattori³, *Ayatoshi Taniguchi¹ (1.Tokai National Higher Education and Research System Nagoya University, 2.Rutherford Appleton Laboratory, 3.Kansai University)

Keywords:solar cycles, grand solar minima, sunspot group number, sunspot positions, Maunder Minimum, Dalton Minimum

We are facing the maximum of Solar Cycle 25. So far, telescopic sunspot observations have captured some 40 solar cycles since 1610. This is unique in comparison with the other observational datasets that form basis for quantification of the past solar observations such as solar radio measurements. These records allow us to reconstruct, quantify, and visualise solar cycles over the last four centuries. However, their reconstructions have considerable variations before the mid 19th century and accommodated considerable data gaps and uncertainty. This poster aims at reviewing recent developments of archival investigations on historical sunspot records, focusing on the Dalton Minimum, the recovery phase of the Maunder Minimum, and the beginning of the 17th century. The recent archival investigations fill their data gaps, cross validate some anomalous features in the Maunder Minimum, and extend our datasets even back to 1607. These datasets offer not only the source data for further recalibrations but also source data to reconstruct almost continuous butterfly diagrams since 1607. These records quantify the past solar cycles and contrast anomalous solar cycles in the Maunder Minimum with regular solar cycles in the other periods.