Chinese sunspot drawings and their digitization–(Ⅱ)accuracy analysis for digitized sunspot hand-drawing records of Yunnan Observatories

作     者：Yang Peng Xiao-Yu Luo Shu-Guang Zeng Lin-Hua Deng Sheng Zheng Gang-Hua Lin Yu-Lin Cheng Jin-Ping Tao Yong-Li Feng Yang Peng;Xiao-Yu Luo;Shu-Guang Zeng;Lin-Hua Deng;Sheng Zheng;Gang-Hua Lin;Yu-Lin Cheng;Jin-Ping Tao;Yong-Li Feng

作者机构：College of ScienceChina Three Gorges UniversityYichang 443002China Yunnan ObservatoriesChinese Academy of SciencesKunming 650216China National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Chongqing University of Arts and SciencesChongqing 402160China 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2020年第20卷第4期

页      面：156-162页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.U1731124,U1531247,11427901 and 11873089) the special foundation work of the Ministry of Science and Technology of China(Grant No.2014FY120300) the 13th Five-year Informatization Plan of Chinese Academy of Sciences(Grant No.XXH13505–04) the Youth Innovation Promotion Association CAS.The hand-drawing historic 

主　　题：sunspots methods:data analysis techniques:image processing 

摘      要：Sunspots are the most striking and easily observed magnetic structures of the Sun,and statistical analysis of solar historical data could reveal a wealth of information on the long-term variation of solar activity *** hand-drawn sunspot records of Yunnan Observatories,Chinese Academy of Sciences have been accumulating for more than 60 years,and nearly 16000 images have been *** the future,the observation mode of recording sunspots by hand-drawing will be replaced inevitably by digital images observed either at ground or in *** connect the hand-drawn sunspot data and the purely digital sunspot data in future,it is necessary to analyze the systematic errors of the data which are observed by the two observation modes in the period of *** this paper,we choose 268 round sunspots(Htype in modified Zurich sunspot classification)from the drawing of Yunnan Observatories to compare their positions and areas with the CCD observations made by Helioseismic and Magnetic Imager(HMI)on board Solar Dynamic Observatory(SDO)and Global Oscillation Network Group(GONG).We find that the latitude and longitude accuracy of hand-drawn sunspot are within-0.127 and 2.29 degree respectively,and the area accuracy is about 16.36 sunspot unit(μHem).Systematic errors apparently decrease with large sunspot.