Interactive annular mode links jet stream-ocean coupling to decadal Northern Hemispheric warmth

Interactive annular mode links jet stream-ocean coupling to decadal Northern Hemispheric warmth | 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 Physical Sciences - Article Interactive annular mode links jet stream-ocean coupling to decadal Northern Hemispheric warmth Tsubasa Kohyama, Yoko Yamagami, Shoichiro Kido, Fumiaki Oqawa, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6248688/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract The atmospheric jet stream governs the distribution and intensity of midlatitude weather systems and climate variability. In the Northern Hemisphere, meridional migrations of the jet stream are directly linked to the frequency and magnitude of extreme weather events. While previous studies have established that jet stream fluctuations are modulated by spatio-temporal variations in diabatic heating, the relationship between low-frequency modes of atmospheric and oceanic variability remains unclear. Here we propose a hypothesis that the Northern Annular Mode (NAM) and the Pacific Decadal Variability (PDV), the most dominant modes of climate variability in the Northern Hemisphere, constitute an annular-shaped air-sea coupled mode. The singular value decomposition analysis of sea surface temperatures and lower tropospheric zonal winds shows that the most dominant covariability over the Northern Hemisphere closely corresponds to both the conventional PDV and NAM patterns. The extracted PDV-like and NAM-like modes explain 46% of each other's variance, suggesting substantial coupling, and we refer to this hypothesized air-sea coupled phenomenon as the interactive Annular Mode (iAM). We detect a positive feedback mechanism that amplifies iAM to be a dominant mode by conducting a heat budget analysis and performing a pacemaker experiment with a high-resolution global climate model. The record-breaking heat waves observed across the Northern Hemisphere in 2024 are attributed to recent prolonged positive phase of iAM. Earth and environmental sciences/Climate sciences/Atmospheric science/Atmospheric dynamics Earth and environmental sciences/Climate sciences/Ocean sciences/Physical oceanography Earth and environmental sciences/Climate sciences/Climate change/Climate and Earth system modelling Earth and environmental sciences/Climate sciences/Climate change/Projection and prediction Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Under Review 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-6248688","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":431757142,"identity":"7b3d6a87-4b7c-466b-b9e9-20205f8b65a0","order_by":0,"name":"Tsubasa Kohyama","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYHACNhAhByYZGyBCBvjU80C1GJOuJbEBWQteYM9/xuzBjz926X38Bxgf/Nxhx8DffoChuACfLRI55oa9bcm5bRIJzIa9Z5IZJM4kMBjPwKuFx0yCt4EZqIWBTZqxjZmB4QbQZzz4tAAdJvnnT306G/8BkJZ6BnmCWhhyzKR52A4nsDEkgLQcZjAgqOVGWrmxbNtxwzaJxGagp47zGJ5JbMDrF/b+w9sevvlTLS/ff/jgg59t1XJyxw8fM8YXYkgAEilAJzG2GROnAwkwPyZZyygYBaNgFAxnAADzAkA1i9bgDgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0002-5606-2062","institution":"Ochanomizu University","correspondingAuthor":true,"prefix":"","firstName":"Tsubasa","middleName":"","lastName":"Kohyama","suffix":""},{"id":431757143,"identity":"314deab7-6232-45fb-9f07-40672272982a","order_by":1,"name":"Yoko Yamagami","email":"","orcid":"","institution":"Japan Agency for Marine-Earth Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Yoko","middleName":"","lastName":"Yamagami","suffix":""},{"id":431757144,"identity":"90882358-ebfe-4d32-95bd-48edbbd6af03","order_by":2,"name":"Shoichiro Kido","email":"","orcid":"https://orcid.org/0000-0001-8313-5207","institution":"Application Laboratory, Research Institute for Value‐Added‐Information Generation, Japan Agency for Marine‐Earth Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Shoichiro","middleName":"","lastName":"Kido","suffix":""},{"id":431757145,"identity":"a3a59acc-6ada-4118-a67a-8a6e1d7b60a0","order_by":3,"name":"Fumiaki Oqawa","email":"","orcid":"","institution":"Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan","correspondingAuthor":false,"prefix":"","firstName":"Fumiaki","middleName":"","lastName":"Oqawa","suffix":""},{"id":431757146,"identity":"3f40bce7-d4b2-47bb-bbd0-72c5421f6ac7","order_by":4,"name":"Hiroaki Miura","email":"","orcid":"","institution":"University of Tokyo","correspondingAuthor":false,"prefix":"","firstName":"Hiroaki","middleName":"","lastName":"Miura","suffix":""}],"badges":[],"createdAt":"2025-03-18 02:40:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6248688/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6248688/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":80014655,"identity":"94fd1fb9-ef0d-418a-b382-d116d71d74a5","added_by":"auto","created_at":"2025-04-07 02:54:11","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2601712,"visible":true,"origin":"","legend":"Article File","description":"","filename":"K24iamver5.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6248688/v1_covered_a03d6a1b-df70-4551-bd06-c6689e71a24b.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Interactive annular mode links jet stream-ocean coupling to decadal Northern Hemispheric warmth","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-6248688/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6248688/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"The atmospheric jet stream governs the distribution and intensity of midlatitude weather systems and climate variability. 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