Multiscale Energetics and Submesoscale Instabilities of Eddy Shedding at the Kuroshio Loop Current in the South China Sea

Multiscale Energetics and Submesoscale Instabilities of Eddy Shedding at the Kuroshio Loop Current in the South China Sea | 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 Multiscale Energetics and Submesoscale Instabilities of Eddy Shedding at the Kuroshio Loop Current in the South China Sea Yunlong Fei, Shaoqing Zhang, Zhengguang Zhang, Yang Gao, Xing Xu, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6884612/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 25 Aug, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract The multiscale energetics and submesoscale instabilities after the eddy shedding of Kuroshio Loop Current (KLC) intrusion into the South China Sea (SCS) remain ambiguous. Here, a typical KLC eddy shedding process is well simulated using a downscaled submesoscale-permitting model. Then, energy and dynamics diagnostics are employed to investigate the cross-scale interactions between mesoscales and submesoscales during and after this process. In energetics, although the forward and inverse energy cascades coexist, the forward cascade of available potential energy (APE) is crucial in energizing submesoscales while the strength of forward kinetic energy (KE) is relatively weak. The submesoscale KE is primarily charged by strong buoyancy conversion and secondarily by horizontal advection from upstream, which is mainly balanced by turbulence dissipation and vertical pressure work. In dynamics, except for the release of submesoscale APE by baroclinic instability, symmetric instability (SI) can extract KE from geostrophic flows and drive forward KE cascades. Specifically, strain-induced advective frontogenesis can rapidly sharpen submesoscales by enhancing lateral buoyancy gradients, the increased baroclinicity together with atmospheric-forced buoyancy loss causes negative total Ertel potential vorticity and creates favorable conditions for SI. These results highlight the significance of submesoscales in multiscale energetics and dynamical instabilities of the KLC eddy shedding. Earth and environmental sciences/Ocean sciences/Physical oceanography Earth and environmental sciences/Ocean sciences High-resolution Kuroshio Loop Current eddy shedding simulation Cross-scale interactions between mesoscales and submesoscales Submesoscale instabilities and forward energy cascade Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 25 Aug, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 09 Jul, 2025 Reviews received at journal 08 Jul, 2025 Reviews received at journal 05 Jul, 2025 Reviewers agreed at journal 21 Jun, 2025 Reviewers agreed at journal 19 Jun, 2025 Reviewers invited by journal 19 Jun, 2025 Editor assigned by journal 18 Jun, 2025 Editor invited by journal 17 Jun, 2025 Submission checks completed at journal 16 Jun, 2025 First submitted to journal 13 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. 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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-6884612","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":474402095,"identity":"b53073ce-2c28-49e4-84a7-e723ce58a145","order_by":0,"name":"Yunlong Fei","email":"","orcid":"","institution":"Ocean University of China","correspondingAuthor":false,"prefix":"","firstName":"Yunlong","middleName":"","lastName":"Fei","suffix":""},{"id":474402096,"identity":"59ce9b25-1ac7-436c-acde-0be1a205baf3","order_by":1,"name":"Shaoqing 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Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"High-resolution Kuroshio Loop Current eddy shedding simulation, Cross-scale interactions between mesoscales and submesoscales, Submesoscale instabilities and forward energy cascade","lastPublishedDoi":"10.21203/rs.3.rs-6884612/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6884612/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe multiscale energetics and submesoscale instabilities after the eddy shedding of Kuroshio Loop Current (KLC) intrusion into the South China Sea (SCS) remain ambiguous. Here, a typical KLC eddy shedding process is well simulated using a downscaled submesoscale-permitting model. Then, energy and dynamics diagnostics are employed to investigate the cross-scale interactions between mesoscales and submesoscales during and after this process.\u003c/p\u003e \u003cp\u003eIn energetics, although the forward and inverse energy cascades coexist, the forward cascade of available potential energy (APE) is crucial in energizing submesoscales while the strength of forward kinetic energy (KE) is relatively weak. The submesoscale KE is primarily charged by strong buoyancy conversion and secondarily by horizontal advection from upstream, which is mainly balanced by turbulence dissipation and vertical pressure work.\u003c/p\u003e \u003cp\u003eIn dynamics, except for the release of submesoscale APE by baroclinic instability, symmetric instability (SI) can extract KE from geostrophic flows and drive forward KE cascades. Specifically, strain-induced advective frontogenesis can rapidly sharpen submesoscales by enhancing lateral buoyancy gradients, the increased baroclinicity together with atmospheric-forced buoyancy loss causes negative total Ertel potential vorticity and creates favorable conditions for SI. These results highlight the significance of submesoscales in multiscale energetics and dynamical instabilities of the KLC eddy shedding.\u003c/p\u003e","manuscriptTitle":"Multiscale Energetics and Submesoscale Instabilities of Eddy Shedding at the Kuroshio Loop Current in the South China Sea","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-23 15:44:36","doi":"10.21203/rs.3.rs-6884612/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-09T08:05:11+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-08T08:11:18+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-05T09:20:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"297655648719853807849584337631531054014","date":"2025-06-21T08:36:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"300364915236554616280063123045098596228","date":"2025-06-20T00:54:34+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-19T05:50:59+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-18T08:34:38+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-06-17T07:19:51+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-16T14:44:56+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-06-13T04:40:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a1d64cab-7df4-4483-b96a-d328391c1765","owner":[],"postedDate":"June 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":50382093,"name":"Earth and environmental sciences/Ocean sciences/Physical oceanography"},{"id":50382094,"name":"Earth and environmental sciences/Ocean sciences"}],"tags":[],"updatedAt":"2025-09-01T16:03:54+00:00","versionOfRecord":{"articleIdentity":"rs-6884612","link":"https://doi.org/10.1038/s41598-025-15739-6","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-08-25 15:58:17","publishedOnDateReadable":"August 25th, 2025"},"versionCreatedAt":"2025-06-23 15:44:36","video":"","vorDoi":"10.1038/s41598-025-15739-6","vorDoiUrl":"https://doi.org/10.1038/s41598-025-15739-6","workflowStages":[]},"version":"v1","identity":"rs-6884612","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6884612","identity":"rs-6884612","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}