Oscillatory Coupling between Solar–Terrestrial Dynamics and El Niño–Southern Oscillation (ENSO) during Equinox Periods: An Astroclimatological Decadal Analysis

Oscillatory Coupling between Solar–Terrestrial Dynamics and El Niño–Southern Oscillation (ENSO) during Equinox Periods: An Astroclimatological Decadal Analysis | 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 Article Oscillatory Coupling between Solar–Terrestrial Dynamics and El Niño–Southern Oscillation (ENSO) during Equinox Periods: An Astroclimatological Decadal Analysis Guillermo A. Chinni This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7110270/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 The El Niño–Southern Oscillation (ENSO) is a major driver of global interannual climate variability. This study investigates the potential influence of solar–terrestrial oscillations—particularly anomalies in solar declination and Earth–Sun distance—during equinox periods from 2013 to 2024. Using satellite-derived net shortwave radiation as an integrative indicator reflecting both atmospheric conditions and astronomical influences, together with precise astronomical ephemerides and polar motion data, a multiple linear regression model captures approximately 70% of the variability in the Oceanic Niño Index (ONI). The model identifies solar declination as the principal astronomical driver, with Earth–Sun distance contributing significantly, and polar motion showing limited influence at the decadal scale, though potentially relevant over longer periods. These findings support an astroclimatological framework in which subtle orbital and axial variations act as persistent and quantifiable modulators of seasonal ENSO phases. Rather than serving as a static backdrop, astronomical factors generate unique annual configurations due to complex orbital and rotational dynamics, resulting in variable solar forcing conditions that affect ocean–atmosphere coupling. Anomalies in net shortwave radiation reflect the dynamic interplay between celestial geometry and geophysical processes, mediating ENSO variability. While this study primarily aimed to analyze the influence of key astronomical variables, it also yielded a model with potential for ENSO prediction. This highlights the value of incorporating astronomical metrics into ENSO analysis, especially during equinoctial transitions. The findings suggest ENSO variability is embedded within a coupled system shaped by persistent astronomical oscillations, reflecting a planetary-scale link between celestial mechanics and climate variability. Earth and environmental sciences/Climate sciences Earth and environmental sciences/Planetary science El Niño–Southern Oscillation (ENSO) Oceanic Niño Index (ONI) Solar declination anomaly Earth–Sun distance Polar motion Net downward shortwave radiation Astroclimatology Equinox transitions Climate variability Full Text Additional Declarations No competing interests reported. Supplementary Files SupplementaryInformationChinniOscillatoryCouplingENSO2025v1.2.docx 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-7110270","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":493930113,"identity":"3423004f-3a4d-49bd-80e7-463b4a778817","order_by":0,"name":"Guillermo A. 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This study investigates the potential influence of solar\u0026ndash;terrestrial oscillations\u0026mdash;particularly anomalies in solar declination and Earth\u0026ndash;Sun distance\u0026mdash;during equinox periods from 2013 to 2024. Using satellite-derived net shortwave radiation as an integrative indicator reflecting both atmospheric conditions and astronomical influences, together with precise astronomical ephemerides and polar motion data, a multiple linear regression model captures approximately 70% of the variability in the Oceanic Ni\u0026ntilde;o Index (ONI). The model identifies solar declination as the principal astronomical driver, with Earth\u0026ndash;Sun distance contributing significantly, and polar motion showing limited influence at the decadal scale, though potentially relevant over longer periods.\u003c/p\u003e\u003cp\u003eThese findings support an astroclimatological framework in which subtle orbital and axial variations act as persistent and quantifiable modulators of seasonal ENSO phases. Rather than serving as a static backdrop, astronomical factors generate unique annual configurations due to complex orbital and rotational dynamics, resulting in variable solar forcing conditions that affect ocean\u0026ndash;atmosphere coupling. Anomalies in net shortwave radiation reflect the dynamic interplay between celestial geometry and geophysical processes, mediating ENSO variability.\u003c/p\u003e\u003cp\u003eWhile this study primarily aimed to analyze the influence of key astronomical variables, it also yielded a model with potential for ENSO prediction. This highlights the value of incorporating astronomical metrics into ENSO analysis, especially during equinoctial transitions. The findings suggest ENSO variability is embedded within a coupled system shaped by persistent astronomical oscillations, reflecting a planetary-scale link between celestial mechanics and climate variability.\u003c/p\u003e","manuscriptTitle":"Oscillatory Coupling between Solar–Terrestrial Dynamics and El Niño–Southern Oscillation (ENSO) during Equinox Periods: An Astroclimatological Decadal Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-04 08:31:35","doi":"10.21203/rs.3.rs-7110270/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5c660e91-bb9b-42aa-ba2f-641834eddf4e","owner":[],"postedDate":"August 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":52458377,"name":"Earth and environmental sciences/Climate sciences"},{"id":52458378,"name":"Earth and environmental sciences/Planetary science"}],"tags":[],"updatedAt":"2025-09-22T16:38:19+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-04 08:31:35","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7110270","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7110270","identity":"rs-7110270","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}