Space Climate 7 Meeting Abstract
Sunspot observations during the Dalton Minimum: a case study by original observational logs
Hisashi Hayakawa (Osaka University)
Tomoya Iju (NAOJ), Rainer Arlt (Potsdam AIP), Shinsuke Imada (Nagoya Univ.)
The solar activity during the Dalton Minimum is of particular interest, due to the decreasing amplitude of recent solar cycles. The amplitude of the solar activity during the Dalton Minimum was reconstructed by a couple of observers during this period, while their data reduction was not necessarily consistent with those for the modern sunspot observations. However, the majority of their observational logs stayed unpublished and made re-assessment of the solar activity during the Dalton Minimum rather difficult. In this presentation, we show case studies for observations by Derfflinger and Flaugergues, two of the most active observers during the Dalton Minimum. We revise their data based on their original records and explain the caveats of these datasets. These case studies show that the amplitude of the solar cycles during the Dalton Minimum should be reconstructed after case studies for primary observers during this period and combining these records with each other, rather than based on a single representative observer's data.
Mode of presentation: poster