Records of sunspot and aurora during CE 960–1279 in the Chinese chronicle of the Sòng dynasty

Hisashi Hayakawa,Hiroaki Isobe,Harufumi Tamazawa,Akito Davis Kawamura

doi:10.1186/s40623-015-0250-y

Abstract

Records of sunspots and aurora observations in pre-telescopic historical documents can provide useful information about solar activity in the past. This is also true for extreme space weather events, as they may have been recorded as large sunspots observed by the naked eye or as low-latitude auroras. In this paper, we present the results of a comprehensive survey of records of sunspots and auroras in the Songshi, a Chinese formal chronicle spanning the tenth to the thirteenth century. This chronicle contains a record of continuous observations with well-formatted reports conducted as a policy of the government. A brief comparison of the frequency of observations of sunspots and auroras and the observations of radioisotopes as an indicator of the solar activity during corresponding periods is provided. This paper is the first step of our project in which we survey and compile the records of sunspots and aurora in historical documents from various locations and languages, ultimately providing it to the science community as online data.

Highlights

Historical solar magnetic activity is of great interest because it provides crucial information on the origin of solar magnetic fields and its variability as well as the relationship of solar activity and the climate of the Earth (Usoskin 2013)
In this paper, we present the data for the formal chronicle of the Sòng dynasty, Sòngshǐ (CE 960–1279), and we compare these results with data from cosmogenic radionuclide studies, such as the one performed by Miyake (2013)
Overall result The lists of the candidates of sunspot and aurora are shown in Tables 1 and 2, respectively

Summary

Introduction

Historical solar magnetic activity is of great interest because it provides crucial information on the origin of solar magnetic fields and its variability as well as the relationship of solar activity and the climate of the Earth (Usoskin 2013). Telescopic sunspot observations have been recorded since the era of Galileo about 400 years ago. The sunspot number is considered to be the standard index of the solar activity (Clette et al 2014), and it is known as the longest-term scientific data (Owens 2013). Eddy (1980) pointed out that pre-telescopic historical records of sunspots, auroras, and total eclipses (shapes of solar corona) could be useful for the reconstruction of the past solar activity. Several authors have published the lists of astronomical events including naked-eye sunspots and auroras in the literature from Japan (Kanda 1933; Matsushita 1956; Nakazawa et al 2004; Shiokawa et al 2005), Korea (Lee et al 2004), Arabic countries (Basurah 2006), Europe

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