A 45-Year Climatological Study of Arctic Stratospheric Polar Vortex Dynamics and Morphology using ERA5 Data (1979-2023)

A 45-Year Climatological Study of Arctic Stratospheric Polar Vortex Dynamics and Morphology using ERA5 Data (1979-2023) | 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 A 45-Year Climatological Study of Arctic Stratospheric Polar Vortex Dynamics and Morphology using ERA5 Data (1979-2023) Anish Kumar, Khalil Karami, Christoph Jacobi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7472791/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 Arctic Stratospheric Polar Vortex (SPV) is known for its high interannual variability, with major Sudden Stratospheric Warmings (SSWs) occurring approximately every second year and with three Exceptionally Strong Vortex (ESV) events in the past decades, which are associated with springtime ozone depletion. Understanding the dynamical and morphological properties of the SPV is crucial for predicting these extreme events, and SPV variability in general. This study utilizes data from 45 Northern Hemisphere (NH) extended winter seasons, covering the period from September to May, at lower, middle and upper stratosphere heights. We explore the influence of different climate variability modes — El Nino-Southern Oscillation, Quasi-Biennial Oscillation, Arctic Oscillation, and Indian Ocean Dipole — on the vortex's dynamical properties. In February, March and April of the 2019 NH winter, the climatological anomaly reached an all-time high of SPV strength, with record-low ozone due to an exceptionally strong vortex, though its intensity did not extend to the upper stratosphere. Other ESV winters were 1996 and 2010. The EPV gradient increases more sharply with altitude than the area, indicating a stronger upper stratospheric vortex boundary that resists tropospheric wave disturbances. During some SSW events, the vortex area may recover, but the EPV gradient remains weak. During the period from 1989 to 1995, no extreme events were recorded, and the SPV strength remained close to the climatological average during the extended winter. The SPV center shows a significant latitudinal shift move away from the pole by the 14.31 km/year. In stable vortex years without SSWs, the center shifts poleward, typically positioned in the western hemisphere. We quantify climatic variability and its role in extreme SPV events, highlighting the significant influence of the Quasi-Biennial Oscillation and Arctic Oscillation. Breakup timing, influenced by tropospheric waves, shows minor variations across levels. The vortex begins forming in the upper levels and dissipates progressively from the lower stratosphere. Notably, a statistically significant decreasing trend towards earlier vortex formation is seen in the upper stratosphere. We quantify the variability in the formation and deformation of the vortex across different levels and analyze the interannual variability of Polar Stratospheric Clouds and their relationship with SPV dynamics and associated ozone loss during late winter and early spring. We hypothesized that both SSWs and ESVs could potentially occur in a single NH winter in future. Climatology Meteorology Atmospheric Sciences stratospheric polar vortex long-term trends extreme events Full Text Additional Declarations The authors declare no competing interests. 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. 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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-7472791","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":506447571,"identity":"e42cde52-b0f3-42d4-b1ca-6f0a1826a864","order_by":0,"name":"Anish Kumar","email":"data:image/png;base64,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","orcid":"https://orcid.org/0009-0002-2279-4932","institution":"Institute for Meteorology, Leipzig University, Leipzig, Germany","correspondingAuthor":true,"prefix":"","firstName":"Anish","middleName":"","lastName":"Kumar","suffix":""},{"id":506447572,"identity":"0faac024-f218-489d-95ab-afdca3e6cacc","order_by":1,"name":"Khalil Karami","email":"","orcid":"","institution":"Institute for Meteorology, Leipzig University, Leipzig, Germany","correspondingAuthor":false,"prefix":"","firstName":"Khalil","middleName":"","lastName":"Karami","suffix":""},{"id":506447573,"identity":"9eb68a92-84a8-4697-a208-8211f6bbc0ca","order_by":2,"name":"Christoph Jacobi","email":"","orcid":"","institution":"Institute for Meteorology, Leipzig University, Leipzig, Germany","correspondingAuthor":false,"prefix":"","firstName":"Christoph","middleName":"","lastName":"Jacobi","suffix":""}],"badges":[],"createdAt":"2025-08-27 14:52:16","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7472791/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7472791/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":90078617,"identity":"e2f2f301-2449-4564-96db-6ebd334244fb","added_by":"auto","created_at":"2025-08-28 08:26:38","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2213984,"visible":true,"origin":"","legend":"","description":"","filename":"ClimateDynamicsERA519792023.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7472791/v1_covered_bfb4ae2f-194a-436a-8917-791b7c8e7b06.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eA 45-Year Climatological Study of Arctic Stratospheric Polar Vortex Dynamics and Morphology using ERA5 Data (1979-2023)\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Institute for Meteorology, Leipzig University, Leipzig, Germany","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"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},"keywords":"stratospheric polar vortex, long-term trends, extreme events","lastPublishedDoi":"10.21203/rs.3.rs-7472791/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7472791/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe Arctic Stratospheric Polar Vortex (SPV) is known for its high interannual variability, with major Sudden Stratospheric Warmings (SSWs) occurring approximately every second year and with three Exceptionally Strong Vortex (ESV) events in the past decades, which are associated with springtime ozone depletion. Understanding the dynamical and morphological properties of the SPV is crucial for predicting\u0026nbsp;these extreme events, and SPV variability in general. This study utilizes data from 45 Northern Hemisphere (NH) extended winter seasons, covering the period from September to May, at lower, middle and upper stratosphere heights. We explore the influence of different climate variability modes — El Nino-Southern Oscillation, Quasi-Biennial Oscillation, Arctic Oscillation, and Indian Ocean Dipole — on the vortex's dynamical properties.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn February, March and April of the 2019 NH winter, the climatological anomaly reached an all-time high of SPV strength, with record-low ozone due to an exceptionally strong vortex, though its intensity did not extend to the upper stratosphere. Other ESV winters were 1996 and 2010. The EPV gradient increases more sharply with altitude than the area, indicating a stronger upper stratospheric vortex boundary that resists tropospheric wave disturbances. During some SSW events, the vortex area may recover, but the EPV gradient remains weak. During the period from 1989 to 1995, no extreme events were recorded, and the SPV strength remained close to the climatological average during the extended winter. The SPV center shows a significant latitudinal shift move away from the pole by the 14.31 km/year. In stable vortex years without SSWs, the center shifts poleward, typically positioned in the western hemisphere.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe quantify climatic variability and its role in extreme SPV events, highlighting the significant influence of the Quasi-Biennial Oscillation and Arctic Oscillation. Breakup timing, influenced by tropospheric waves, shows minor variations across levels. The vortex begins forming in the upper levels and dissipates progressively from the lower stratosphere. Notably, a statistically significant decreasing trend \u0026nbsp;towards earlier vortex formation is seen in the upper stratosphere. We quantify the variability in the formation and deformation of the vortex across different levels and analyze the interannual variability of Polar Stratospheric Clouds and their relationship with SPV dynamics and associated ozone loss during late winter and early spring. We hypothesized that both SSWs and ESVs could potentially occur in a single NH winter in future.\u003c/p\u003e","manuscriptTitle":"A 45-Year Climatological Study of Arctic Stratospheric Polar Vortex Dynamics and Morphology using ERA5 Data (1979-2023)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-28 08:18:29","doi":"10.21203/rs.3.rs-7472791/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":"ba0c91ff-281c-49c5-be4c-e47775115085","owner":[],"postedDate":"August 28th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":53794989,"name":"Climatology"},{"id":53794990,"name":"Meteorology"},{"id":53794991,"name":"Atmospheric Sciences"}],"tags":[],"updatedAt":"2025-08-28T08:18:29+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-28 08:18:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7472791","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7472791","identity":"rs-7472791","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}