Oceanic Fronts Shape Hemispheric Contrasts in Polar Stratospheric Extremes

Oceanic Fronts Shape Hemispheric Contrasts in Polar Stratospheric Extremes | 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 Oceanic Fronts Shape Hemispheric Contrasts in Polar Stratospheric Extremes Nour-Eddine Omrani, Fumiaki Oqawa, Hisashi Nakamura, Noel Keenlyside, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6253791/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 Extreme stratospheric events such as Sudden Stratospheric Warmings (SSWs) and Polar Stratospheric Clouds (PSCs) exhibit striking inter-hemispheric asymmetries: SSWs are frequent in the Arctic but rare in the Antarctic, while PSCs are more persistent in the Antarctic. Although land-sea thermal contrast and orography (LSCO) have been traditionally invoked to explain these asymmetries, we show that LSCO alone cannot fully account for the observed differences. Using targeted model experiments, we reveal that midlatitude oceanic Sea Surface Temperature (SST) fronts represent a crucial but overlooked additional driver of hemispheric stratospheric differences. Like LSCO, SST fronts enhance stratospheric convergence of planetary wave activity, strengthening the Brewer-Dobson Circulation and inducing high-latitude adiabatic warming. This warming significantly enhances Arctic SSW frequency and strongly reduces PSC formation. The oceanic impact is dominated by Pacific SST fronts. Our results highlight the indispensable role of SST fronts in shaping Arctic-Antarctic asymmetries in stratospheric dynamics and associated extremes . Earth and environmental sciences/Climate sciences/Atmospheric science/Atmospheric dynamics Earth and environmental sciences/Climate sciences/Ocean sciences Earth and environmental sciences/Climate sciences/Atmospheric science/Atmospheric chemistry Earth and environmental sciences/Environmental sciences/Environmental impact Full Text Additional Declarations There is NO Competing Interest. Supplementary Files Suppl2025PSCsSSW.docx Oceanic Fronts Shape Hemispheric Contrasts in Polar Stratospheric Extremes 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. 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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-6253791","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":438494602,"identity":"0c48e974-1670-4b07-a7b3-6f5f4feab845","order_by":0,"name":"Nour-Eddine 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