Long-Term Variability of Atmospheric Refractivity and Gradients from Tropics to Poles: A 31 Year Analysis

Long-Term Variability of Atmospheric Refractivity and Gradients from Tropics to Poles: A 31 Year 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 Long-Term Variability of Atmospheric Refractivity and Gradients from Tropics to Poles: A 31 Year Analysis Solomon O. Adeola, Jacob A. Akinpelu, Francis O. Aweda, Saeed A. Bello, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8752891/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Atmospheric refractivity and its vertical changes play an important role in how radio waves travel, but detailed studies across different climate regions are still limited. This study provides a long-term analysis of refractivity, its vertical gradients, and k-factor changes across five major climate zones: tropical, arid, temperate, subarctic, and polar. Using several decades of atmospheric data, we analyze vertical structures, seasonal patterns, year-to-year changes, and extreme conditions, and relate them to physical processes in the atmosphere that affect radio-wave behavior. The results show that tropical regions have the strongest negative refractivity gradients near the surface (–54.6 N/km) and the highest occurrence of super-refraction, mainly due to the combined effects of high humidity and temperature, especially during wet-season convection. In contrast, arid and polar regions are mainly influenced by temperature, showing more frequent sub-refraction and weaker seasonal changes. Temperate and subarctic regions show mixed characteristics, influenced by both moisture and temperature layering. Year-to-year variations in tropical and arid regions are linked to ENSO events, while polar regions experience strong variability due to temperature inversions and Arctic warming. The vertical profiles indicate that the effect of moisture decreases with height, and refractivity values in the upper troposphere become similar across all climate zones, highlighting the layered structure of abnormal propagation. The study also finds that standard models, such as ITU-R P.453, tend to underestimate near-surface super-refraction in tropical areas and oversimplify conditions in arid and polar regions. These findings highlight the need for climate-specific refractivity models and provide useful guidance for improving radio-wave prediction and communication system design in different environmental settings. Earth and environmental sciences/Climate sciences Earth and environmental sciences/Environmental sciences Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 11 Mar, 2026 Reviews received at journal 09 Mar, 2026 Reviews received at journal 03 Mar, 2026 Reviewers agreed at journal 16 Feb, 2026 Reviewers agreed at journal 09 Feb, 2026 Reviewers invited by journal 06 Feb, 2026 Editor invited by journal 05 Feb, 2026 Editor assigned by journal 02 Feb, 2026 Submission checks completed at journal 02 Feb, 2026 First submitted to journal 31 Jan, 2026 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-8752891","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":592267937,"identity":"d49d6954-c416-4619-8d0e-a13f6f0de40a","order_by":0,"name":"Solomon O. 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