The Energetics of the 1998 Pacific Decadal Transition

The Energetics of the 1998 Pacific Decadal Transition | 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PDF Research Article The Energetics of the 1998 Pacific Decadal Transition Steven Mauget This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4220062/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 To trace the energetics of the 1998 shift in Pacific decadal variability (PDV), monthly ocean assimilation, atmospheric reanalysis, and satellite-derived cloud cover and radiative data was analyzed. Data during 1980-2021 showed evidence of the Pacific Walker circulation abruptly forcing the equatorial Pacific Ocean into a persistently elevated energy state after 1998. This occurred as a step-like shift to stronger trade winds, positive SOI, and increased central equatorial Pacific (CEP) 500 mb subsidence (w500), accompanied by a significant 25% increase in mean equatorial Pacific oceanic available potential energy (OAPE). Covarying (|r| > 0.6) CEP w500, fractional cloud cover, top-of-atmosphere albedo, and surface short-wave absorbed radiative energy (SWARS) indicate a control of CEP Walker subsidence on CEP SWARS via a subsidence-albedo effect. Similarly correlated CEP SWARS and OAPE (r = 0.670), and a 71 exa Joule (eJ) increase in mean CEP SWARS after 1998 that is two orders of magnitude greater than the increase in mean OAPE (0.507 eJ), suggests the post-1998 strong Walker PDV phase was radiatively driven. Together, this is interpreted as evidence of a positive Walker radiative-dynamic feedback over the equatorial Pacific after 1998. The 1998 shift’s circumstances suggest the influence of persistent 1998-2001 La Niña conditions in tipping PDV from a climatically weak-Walker phase to a strong-Walker phase. Based on these results, and previous work that studied the 1976-1977 PDV transition, a preliminary hypothesis is proposed of PDV as a bi-stable radiative climate mechanism governed by Walker-driven subsidence-albedo variation and ENSO-related tipping events. Pacific decadal variability Walker circulation Cloud radiative effects Oceanic available potential energy Full Text 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-4220062","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":288271902,"identity":"c333ecda-d716-4658-94f9-a950f7a7b417","order_by":0,"name":"Steven Mauget","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA30lEQVRIiWNgGAWjYBCDen72BiBlYEG0DoMEyZ4DIFqCBC0GMxJADCK0yE87/EzyS8WfPAPJ51c3/CiQYOBv707Ab/ztNDNpmTMGxebSOWU3e4AOkzhzdgN+LdIJZtKSbQaMO2fnpN3gAWoxkMjFr0V+dvo3acl/Bowbbp5Ju/mHGC0Mt3PMJD82GCRuuMF+7DZRthjczim2ZjhmbCzZk8N2W8ZAgoegX4AO23jzR42cHD/78Wc33/yxkeNv7yXgMCBg5gFTPAZgkqByEGD8AabYHxClehSMglEwCkYeAABgNkcv/N5+ZwAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-1056-8495","institution":"USDA-ARS: USDA Agricultural Research Service (Retired)","correspondingAuthor":true,"prefix":"","firstName":"Steven","middleName":"","lastName":"Mauget","suffix":""}],"badges":[],"createdAt":"2024-04-05 00:04:49","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4220062/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4220062/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":56841896,"identity":"0a6191fd-813f-4068-beb1-22f1bada76aa","added_by":"auto","created_at":"2024-05-21 07:04:32","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1894277,"visible":true,"origin":"","legend":"","description":"","filename":"Draft8Figs.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4220062/v1_covered_7815f975-ecb0-411f-bea9-2e97cb2e2b20.pdf"}],"financialInterests":"","formattedTitle":"The Energetics of the 1998 Pacific Decadal Transition","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":"Pacific decadal variability, Walker circulation, Cloud radiative effects, Oceanic available potential energy","lastPublishedDoi":"10.21203/rs.3.rs-4220062/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4220062/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"To trace the energetics of the 1998 shift in Pacific decadal variability (PDV), monthly ocean assimilation, atmospheric reanalysis, and satellite-derived cloud cover and radiative data was analyzed. 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