Hemispheric Asymmetry of Relative Sunspot Numbers during Solar Cycles 17–25
The hemispheric asymmetry of solar activity provides important diagnostics of solar dynamo processes. In this study, we present a phase-resolved statistical analysis of hemispheric sunspot number asymmetry over solar cycles 17–25 (1939–2024), using monthly mean data from the National Astronomical Ob...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Supplement Series |
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| Online Access: | https://doi.org/10.3847/1538-4365/adf105 |
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| author | Wenhua Wang Linhua Deng Zuo Jiang Jinlei Li Xinhua Zhao Tingting Xu Miao Wan Jie Cao Nanbin Xiang Xuewen Tan Wei Zhou Weihong Zhou |
| author_facet | Wenhua Wang Linhua Deng Zuo Jiang Jinlei Li Xinhua Zhao Tingting Xu Miao Wan Jie Cao Nanbin Xiang Xuewen Tan Wei Zhou Weihong Zhou |
| author_sort | Wenhua Wang |
| collection | DOAJ |
| description | The hemispheric asymmetry of solar activity provides important diagnostics of solar dynamo processes. In this study, we present a phase-resolved statistical analysis of hemispheric sunspot number asymmetry over solar cycles 17–25 (1939–2024), using monthly mean data from the National Astronomical Observatory of Japan. By combining normalized asymmetry indices, cumulative deviation tracking, and year-by-year significance testing, we identify four key results: (1) the northern hemisphere consistently dominates during the ascending phases of most cycles, suggesting a preferential emergence of magnetic flux at the northern hemisphere; (2) the hemispheric asymmetry significantly diminishes during polarity reversal periods, indicating a balancing effect of global magnetic reconfiguration; (3) solar cycles 23 and 25 exhibit remarkably similar asymmetry patterns, implying solar cycle 25 is likely to be similar to solar cycle 23; and (4) the strength of hemispheric dominance correlates with the overall solar activity level, with stronger asymmetries observed during high-activity phases and weaker signals near solar minima. These findings offer new observational constraints for modeling hemispheric solar dynamics and establish a reproducible, scalable framework for future investigations of long-term solar magnetic asymmetries. |
| format | Article |
| id | doaj-art-5668d307e766413e8e8c6c23e1f8afea |
| institution | Kabale University |
| issn | 0067-0049 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Supplement Series |
| spelling | doaj-art-5668d307e766413e8e8c6c23e1f8afea2025-08-21T05:49:28ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492025-01-0128012010.3847/1538-4365/adf105Hemispheric Asymmetry of Relative Sunspot Numbers during Solar Cycles 17–25Wenhua Wang0https://orcid.org/0009-0002-0764-1508Linhua Deng1https://orcid.org/0000-0003-4407-8320Zuo Jiang2https://orcid.org/0009-0006-1531-5592Jinlei Li3https://orcid.org/0009-0000-9563-293XXinhua Zhao4https://orcid.org/0000-0002-9977-2646Tingting Xu5https://orcid.org/0000-0002-9997-9524Miao Wan6https://orcid.org/0000-0001-8865-1497Jie Cao7https://orcid.org/0009-0000-7057-8084Nanbin Xiang8https://orcid.org/0000-0001-9062-7453Xuewen Tan9https://orcid.org/0000-0002-4710-2325Wei Zhou10https://orcid.org/0009-0005-4190-2312Weihong Zhou11https://orcid.org/0009-0003-2287-6441School of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnSchool of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnSchool of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnSchool of Geophysics and Information Technology, China University of Geosciences , Beijing 100083, People’s Republic of China; State Key Laboratory of Solar Activity and Space Weather , National Space Science Center, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China; Key Laboratory of Solar Activity and Space Weather, National Space Science Center , Chinese Academy of Sciences, Beijing 100190, People’s Republic of ChinaState Key Laboratory of Solar Activity and Space Weather , National Space Science Center, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China; Radio Science and Technology Center (π Center) , Chengdu, Sichuan, 610041, People’s Republic of ChinaSchool of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnSchool of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnSchool of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnYunnan Observatories , Chinese Academy of Sciences, Kunming 650216, People’s Republic of ChinaSchool of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnSchool of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnSchool of Mathematics and Computer Science, Yunnan Minzu University , Kunming 650504, People’s Republic of China ; linhua.deng@ymu.edu.cnThe hemispheric asymmetry of solar activity provides important diagnostics of solar dynamo processes. In this study, we present a phase-resolved statistical analysis of hemispheric sunspot number asymmetry over solar cycles 17–25 (1939–2024), using monthly mean data from the National Astronomical Observatory of Japan. By combining normalized asymmetry indices, cumulative deviation tracking, and year-by-year significance testing, we identify four key results: (1) the northern hemisphere consistently dominates during the ascending phases of most cycles, suggesting a preferential emergence of magnetic flux at the northern hemisphere; (2) the hemispheric asymmetry significantly diminishes during polarity reversal periods, indicating a balancing effect of global magnetic reconfiguration; (3) solar cycles 23 and 25 exhibit remarkably similar asymmetry patterns, implying solar cycle 25 is likely to be similar to solar cycle 23; and (4) the strength of hemispheric dominance correlates with the overall solar activity level, with stronger asymmetries observed during high-activity phases and weaker signals near solar minima. These findings offer new observational constraints for modeling hemispheric solar dynamics and establish a reproducible, scalable framework for future investigations of long-term solar magnetic asymmetries.https://doi.org/10.3847/1538-4365/adf105Sunspot numberSolar cycleSolar magnetic fields |
| spellingShingle | Wenhua Wang Linhua Deng Zuo Jiang Jinlei Li Xinhua Zhao Tingting Xu Miao Wan Jie Cao Nanbin Xiang Xuewen Tan Wei Zhou Weihong Zhou Hemispheric Asymmetry of Relative Sunspot Numbers during Solar Cycles 17–25 The Astrophysical Journal Supplement Series Sunspot number Solar cycle Solar magnetic fields |
| title | Hemispheric Asymmetry of Relative Sunspot Numbers during Solar Cycles 17–25 |
| title_full | Hemispheric Asymmetry of Relative Sunspot Numbers during Solar Cycles 17–25 |
| title_fullStr | Hemispheric Asymmetry of Relative Sunspot Numbers during Solar Cycles 17–25 |
| title_full_unstemmed | Hemispheric Asymmetry of Relative Sunspot Numbers during Solar Cycles 17–25 |
| title_short | Hemispheric Asymmetry of Relative Sunspot Numbers during Solar Cycles 17–25 |
| title_sort | hemispheric asymmetry of relative sunspot numbers during solar cycles 17 25 |
| topic | Sunspot number Solar cycle Solar magnetic fields |
| url | https://doi.org/10.3847/1538-4365/adf105 |
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