Influence of the Eurasian Wave Trains on Summer Rainfall Extremes Along East Asian Quasi-Stationary Rainy Fronts from 1991 to 2024

Influence of the Eurasian Wave Trains on Summer Rainfall Extremes Along East Asian Quasi-Stationary Rainy Fronts from 1991 to 2024 | 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 Influence of the Eurasian Wave Trains on Summer Rainfall Extremes Along East Asian Quasi-Stationary Rainy Fronts from 1991 to 2024 Jae-Hee Cho, Hak-Sung Kim This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7323603/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 During the early summer monsoon in East Asia, quasi-stationary frontal precipitation in July accounted for approximately 41% of Korea’s total summer rainfall from 1991 to 2024. Despite the inclusion of the global warming hiatus within this period, interannual trends in frontal rainfall were not statistically significant over Korea or most of East Asia. We found that changes in the meridional temperature gradient, resulting from pronounced warming or cooling north of 40°N, contributed to shifts in both the location and intensity of the rainy front. In extreme positive precipitation years in Korea (EPP-K), a sequence of alternating near-surface air temperature anomalies across the Eurasian continent intensified a wave-3 Eurasian wave train, forcing wave activity into the mid-latitude regions. Blocking highs over eastern Siberia, induced by this wave train, triggered mid-Siberian cooling intrusions north of East Asia, thereby enhancing the meridional temperature gradient near the quasi-stationary rainy front over the Yellow Sea–Korea (YK) region. The enhanced southwesterly moisture convergence promoted frequent mesoscale convective clouds and associated EPP-K events. Under these conditions, increased convergence of anthropogenic aerosols via southwesterly flows facilitated aerosol–cloud interactions, promoting cloud droplet formation and increasing rainfall efficiency by 24.9%. Conversely, during extreme negative precipitation years (ENP-K), broad near-surface warming across the high- to mid-latitudes of the Eurasian continent strengthened a wave-5 Eurasian wave train, resulting in weakened wave flux compared with EPP-K events and further weakening the meridional temperature gradient near the rainy front over the YK region. The reduced southwesterly moisture convergence limited the development of mesoscale convective clouds, resulting in ENP-K events. Although anthropogenic aerosols—primarily emitted from eastern China—continued to be advected toward the YK region even during the rainy season, the warming-induced stable atmospheric conditions inhibited cloud development and further suppressed precipitation by 7.5%. These findings underscore the critical roles of the surface warming in the Eurasian continent and aerosol–cloud microphysical processes in shaping extreme wet and dry anomalies of East Asian summer frontal rainfall. 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: 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. 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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-7323603","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":517872534,"identity":"983aebb8-3f12-4b63-95f0-52da6c625627","order_by":0,"name":"Jae-Hee Cho","email":"","orcid":"","institution":"Kongju National University","correspondingAuthor":false,"prefix":"","firstName":"Jae-Hee","middleName":"","lastName":"Cho","suffix":""},{"id":517872535,"identity":"18a1e7d1-9f69-4a95-8ea8-bd47a1966b60","order_by":1,"name":"Hak-Sung 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2024","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"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":"","lastPublishedDoi":"10.21203/rs.3.rs-7323603/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7323603/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDuring the early summer monsoon in East Asia, quasi-stationary frontal precipitation in July accounted for approximately 41% of Korea\u0026rsquo;s total summer rainfall from 1991 to 2024. Despite the inclusion of the global warming hiatus within this period, interannual trends in frontal rainfall were not statistically significant over Korea or most of East Asia. We found that changes in the meridional temperature gradient, resulting from pronounced warming or cooling north of 40\u0026deg;N, contributed to shifts in both the location and intensity of the rainy front. In extreme positive precipitation years in Korea (EPP-K), a sequence of alternating near-surface air temperature anomalies across the Eurasian continent intensified a wave-3 Eurasian wave train, forcing wave activity into the mid-latitude regions. Blocking highs over eastern Siberia, induced by this wave train, triggered mid-Siberian cooling intrusions north of East Asia, thereby enhancing the meridional temperature gradient near the quasi-stationary rainy front over the Yellow Sea\u0026ndash;Korea (YK) region. The enhanced southwesterly moisture convergence promoted frequent mesoscale convective clouds and associated EPP-K events. Under these conditions, increased convergence of anthropogenic aerosols via southwesterly flows facilitated aerosol\u0026ndash;cloud interactions, promoting cloud droplet formation and increasing rainfall efficiency by 24.9%. Conversely, during extreme negative precipitation years (ENP-K), broad near-surface warming across the high- to mid-latitudes of the Eurasian continent strengthened a wave-5 Eurasian wave train, resulting in weakened wave flux compared with EPP-K events and further weakening the meridional temperature gradient near the rainy front over the YK region. The reduced southwesterly moisture convergence limited the development of mesoscale convective clouds, resulting in ENP-K events. Although anthropogenic aerosols\u0026mdash;primarily emitted from eastern China\u0026mdash;continued to be advected toward the YK region even during the rainy season, the warming-induced stable atmospheric conditions inhibited cloud development and further suppressed precipitation by 7.5%. These findings underscore the critical roles of the surface warming in the Eurasian continent and aerosol\u0026ndash;cloud microphysical processes in shaping extreme wet and dry anomalies of East Asian summer frontal rainfall.\u003c/p\u003e","manuscriptTitle":"Influence of the Eurasian Wave Trains on Summer Rainfall Extremes Along East Asian Quasi-Stationary Rainy Fronts from 1991 to 2024","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-25 22:40:44","doi":"10.21203/rs.3.rs-7323603/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":"cb69b24c-fb14-4dd0-b1c4-940ceb43f233","owner":[],"postedDate":"September 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":55038968,"name":"Earth and environmental sciences/Climate sciences"},{"id":55038969,"name":"Earth and environmental sciences/Environmental sciences"}],"tags":[],"updatedAt":"2025-10-22T10:23:46+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-25 22:40:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7323603","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7323603","identity":"rs-7323603","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}