Butterfly Diagram and other properties of plagecareas from Kodaikanal Ca II K Photographs Coveringc1904 – 2007

Butterfly Diagram and other properties of plagecareas from Kodaikanal Ca II K Photographs Coveringc1904 – 2007 | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Butterfly Diagram and other properties of plagecareas from Kodaikanal Ca II K Photographs Coveringc1904 – 2007 Bibhuti Kumar Jha, Theodosios Chatzistergos, Dipankar Banerjee, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4775304/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Dec, 2024 Read the published version in Solar Physics → Version 1 posted 7 You are reading this latest preprint version Abstract Ca II K observations of the Sun have a great potential for probing the Sun's magnetism and activity, as well as for reconstructing solar irradiance. The Kodaikanal Solar Observatory (KoSO) in India, houses one of the most prominent \ca archives, spanning from 1904 to 2007, obtained under the same experimental conditions over a century, a feat very few other sites have achieved. However, the KoSO Ca II K archive suffers from several inconsistencies (e.g., missing/incorrect timestamps of observations and orientation of some images) which have limited the use of the archive. This study is a step towards bringing the KoSO archive to its full potential.We did this by developing an automatic method to orient the images more accurately than in previous studies. Furthermore, we included more data than in earlier studies (considering images that could not previously be analyzed by other techniques as well as 2845 newly digitized images), while also accounting for mistakes in the observational date/time. These images were accurately processed to identify plage regions along with their locations, enabling us to construct the butterfly diagram of plage areas from the entire KoSO Ca II K archive covering 1904-–2007.Our butterfly diagram shows significantly fewer data gaps compared to earlier versions due to the larger set of data used in this study. Moreover, our butterfly diagram is consistent with Spörer's law for sunspots, validating our automatic image orientation method. Additionally, we found that the mean latitude of plage areas calculated over the entire period is 20.5%+/-2.0 higher than that of sunspots, irrespective of the phase or the strength of the solar cycle. We also studied the North-South asymmetry showing that the northern hemisphere dominated plage areas during solar cycles 19 and 20, while the southern hemisphere dominated during solar cycles 21--23. Chromosphere Quiet Chromosphere Active Solar Cycle Observations Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 13 Dec, 2024 Read the published version in Solar Physics → Version 1 posted Editorial decision: Revision requested 30 Sep, 2024 Reviews received at journal 19 Sep, 2024 Reviewers agreed at journal 14 Aug, 2024 Reviewers invited by journal 30 Jul, 2024 Editor assigned by journal 24 Jul, 2024 Submission checks completed at journal 24 Jul, 2024 First submitted to journal 21 Jul, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4775304","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":340245814,"identity":"4fb7bf50-497c-4b19-a98a-7dc82d2716f3","order_by":0,"name":"Bibhuti Kumar Jha","email":"","orcid":"","institution":"Southwest Research Institute","correspondingAuthor":false,"prefix":"","firstName":"Bibhuti","middleName":"Kumar","lastName":"Jha","suffix":""},{"id":340245815,"identity":"e8bb51fb-1209-47c9-9de8-541dacf2f42c","order_by":1,"name":"Theodosios Chatzistergos","email":"data:image/png;base64,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","orcid":"","institution":"Max Planck Institute for Solar System Research","correspondingAuthor":true,"prefix":"","firstName":"Theodosios","middleName":"","lastName":"Chatzistergos","suffix":""},{"id":340245816,"identity":"d6fb7600-5dca-41e9-94f0-f52edc4affd4","order_by":2,"name":"Dipankar Banerjee","email":"","orcid":"","institution":"Aryabhatta Research Institute of Observational Sciences","correspondingAuthor":false,"prefix":"","firstName":"Dipankar","middleName":"","lastName":"Banerjee","suffix":""},{"id":340245817,"identity":"96dd7be3-4f54-446a-a2bc-8cb353dbbbce","order_by":3,"name":"Ilaria Ermolli","email":"","orcid":"","institution":"Astronomical Observatory of Rome","correspondingAuthor":false,"prefix":"","firstName":"Ilaria","middleName":"","lastName":"Ermolli","suffix":""},{"id":340245818,"identity":"6ea3a5c9-99d0-40ee-b2a5-e2aad97e3a0d","order_by":4,"name":"Natalie A. 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