Calculating the Strength of Solar Cycle 25: 365-Day High-Resolution Sunspot Smoothing and its Relationship with the 10.7cm Solar Flux

Calculating the Strength of Solar Cycle 25: 365-Day High-Resolution Sunspot Smoothing and its Relationship with the 10.7cm Solar Flux | 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 Calculating the Strength of Solar Cycle 25: 365-Day High-Resolution Sunspot Smoothing and its Relationship with the 10.7cm Solar Flux Patrick Geryl This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5148729/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In our previous research, we identified a correlation between the ratio of the proxy monthly sunspot number to the proxy monthly adjusted solar flux and the onset of sunspot cycles. This offered an early indication with an accuracy of 3 months for the start of a sunspot cycle. In this study, we substitute the conventional 13-month running mean with a 365-day smoothed average to demonstrate that sunspots and the adjusted 10.7 solar flux data share a common starting point for a cycle. This finding is validated by four data solar proxy data sets, namely the minimum values from the 365-day smoothed adjusted solar radio flux, Boulder sunspot number (SSN), 1K and 2K high-resolution SSNs, which all occur on the same day: November 17, 2019. Solar Cycle 25 commenced at this juncture, and the cycle's increasing intensity can be ascertained by measuring the 365-day smoothed strengths 120, 230 and 270 days after its initiation. By analysing these measurements alongside subsequent values that show either reduced or increased rates of strength growth, particularly the 365-day smoothed strength calculable 734 days after the start, a new approach for predicting the intensity of the upcoming cycle has been developed. This approach enables predictions for solar Cycles 19, 20, 22 and 24 to deviate by less than 4.6% from their actual cycle maxima, while the prediction for Cycles 21 and 23 exhibited a deviation of 5.0%. Additionally, this method permits the calculation of the upper limit of the strength prediction in advance, with a lead time ranging from 1.7 to 4.0 months. As a result, we have obtained a 365-day smoothed adjusted flux that is 55.4 percent (given a base solar flux level of 64) higher than Solar Cycle 24, amounting to a peak value of 190.6 sfu (or between 181.5 and 200.6 sfu with a 5 percent margin of error) for Solar Cycle 25. Furthermore, we have determined that the cycle's peak will occur approximately in January 2025. The corresponding peak values for the 1K and 2K sunspot numbers are 253.3 SSN and 388.5 SSN, respectively. However, as Solar Cycle 25 advances, an unusual large disparity has been detected between the 10.7 solar flux and both the International Sunspot Number (ISN) and high-resolution SSNs. This phenomenon necessitates consideration of its potential to indicate an impending anomalous event. Sunspot Cycles 13-month smoothed averages 10.7cm solar flux axial dipole field high-resolution sunspots 365-day smoothing Full Text Additional Declarations No competing interests reported. Supplementary Files Cycle25.xlsx JanAlvestadFlux.xlsx DifferencesCycle24.xlsx Precursorforecast.xlsx JanAlvestad3651.xlsx JanAlvestadFormulaFluxFINAL.xlsx SolarFluxDifference.xlsx Cite Share Download PDF Status: Posted Version 1 posted 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-5148729","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":432969497,"identity":"1d27d510-7114-4c9b-a7f1-5abaae2fd657","order_by":0,"name":"Patrick 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