Asymmetric Atlantic-Pacific interactions on decadal timescales underrepresented in climate models

Asymmetric Atlantic-Pacific interactions on decadal timescales underrepresented in climate models | 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 Asymmetric Atlantic-Pacific interactions on decadal timescales underrepresented in climate models Yan Xia, YONG FU LIN, Jin-Yi Yu, Yunfan Chen, Michael Pritchard This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9489113/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 Observed tropical Pacific sea surface temperatures have exhibited a sustained La Niña–like cooling trend in the eastern Pacific since 1980, whereas coupled climate models simulate an El Niño–like warming pattern under greenhouse forcing. Atlantic warming has been proposed as a driver of this Pacific cooling through inter-basin teleconnections, yet climate models substantially underestimate this influence. Here we show that Atlantic–Pacific interactions are strongly asymmetric on decadal timescales. Lead–lag analyses of observations and CMIP6 simulations reveal two pathways linking the basins: a short-lag atmospheric bridge through which Pacific variability affects the Atlantic, and a delayed ocean-mediated pathway through which Atlantic variability drives Pacific changes. While CMIP6 models reproduce the Pacific-to-Atlantic response, they fail to sustain the delayed Atlantic-to-Pacific pathway evident in observations. This failure arises primarily from underestimated Atlantic convective sensitivity (~30% of observed), compounded by a weak Bjerknes feedback (~82% of observed), which together prevent sustained thermocline adjustment and subsurface ocean memory in the tropical Pacific. The resulting underrepresentation of the Atlantic-to-Pacific pathway helps explain why climate models struggle to reproduce the observed La Niña–like tropical Pacific trend. Earth and environmental sciences/Climate sciences/Climate change/Climate and Earth system modelling Earth and environmental sciences/Climate sciences Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SIAsymmetricAtlanticPacificinteractionsondecadaltimescalesunderrepresentedinclimatemodelssubmit.docx Asymmetric Atlantic-Pacific interactions on decadal timescales underrepresented in climate models 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. 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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-9489113","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":628997498,"identity":"43e69bf2-6c9a-4ade-99e5-f912cd9e2ac6","order_by":0,"name":"Yan 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