Influence of Subtropical Westerlies on the Equatorial Wave Spectrum: implications for future changes in Kelvin wave variance

Influence of Subtropical Westerlies on the Equatorial Wave Spectrum: implications for future changes in Kelvin wave variance | 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 Influence of Subtropical Westerlies on the Equatorial Wave Spectrum: implications for future changes in Kelvin wave variance Hagar Bartana, Chaim Garfinkel, Chen Schwartz, Ofer Shamir, Jian Rao This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6767382/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Models from phase 6 of the Coupled Model Intercomparison Project (CMIP6), simulate an intensification in equatorial Kelvin Waves (KW) with global warming. In contrast, the power spectrum is projected to weaken for most other wavenumber-frequency combinations, including higher wavenumber Equatorial Rossby waves (ER). The qualitatively different projected responses of KW and ER suggest that dynamical forcings play an important role in the physical mechanism of the changes. This hypothesis is tested using targeted simulations of the Model of an Idealized Moist Atmosphere (MiMA) in which we impose perturbations in upper-tropospheric zonal winds that mimic projected end-of-century changes. These simulations demonstrate that future changes in KW depend on changes in the Southern Hemisphere subtropical jet. A similar dependence is also evident in CMIP6 models. These results have implications for future projections of KW activity in models with biased subtropical westerlies. Convectively coupled equatorial waves Kelvin waves Madden-Julian Oscillation Equatorial spectrum southern hemisphere subtropical jet Full Text Additional Declarations Supplementary file 1 is not available with this version. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major Revision 10 Sep, 2025 Reviewers agreed at journal 30 Jul, 2025 Reviewers invited by journal 07 Jul, 2025 Editor assigned by journal 24 Jun, 2025 First submitted to journal 23 Jun, 2025 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. 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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-6767382","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":481994342,"identity":"88bad8d0-b688-429a-82d9-71ead745d5be","order_by":0,"name":"Hagar 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