Evaluation of CMIP6 Model Performance and Future Climate Projections over the Genale Dawa River Basin, Ethiopia

Evaluation of CMIP6 Model Performance and Future Climate Projections over the Genale Dawa River Basin, Ethiopia | 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 Evaluation of CMIP6 Model Performance and Future Climate Projections over the Genale Dawa River Basin, Ethiopia Fetene Muluken Chanie This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6764974/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 04 Dec, 2025 Read the published version in Scientific Reports → Version 1 posted 13 You are reading this latest preprint version Abstract The Genale Dawa River Basin (GDRB) in southeastern Ethiopia is highly vulnerable to climate variability. Yet, limited research has assessed how well the latest CMIP6 climate models simulate key variables in this complex, data-scarce region, posing challenges for effective climate risk assessment and adaptation planning. This study evaluates the performance of 12 CMIP6 Global Climate Models (GCMs) in simulating historical precipitation, maximum temperature (Tmax), and minimum temperature (Tmin) over the GDRB for the baseline period 1985–2014. Future projections are also assessed for 2021–2050 and 2051–2080 under two emission scenarios: SSP2-4.5 and SSP5-8.5. Observational data from ENACTS and 60 ground-based stations were used to validate model outputs, which were re-gridded to 0.5° × 0.5° and bias-corrected using quantile mapping. Model performance was assessed using Mean Bias Error (MBE), Root Mean Square Error (RMSE), Pearson correlation, Taylor Skill Score (TSS), and visual diagnostics. The multi-model ensemble (MME) outperformed individual GCMs, with TSS values of 0.80 for precipitation, 0.98 for Tmax, and 0.99 for Tmin. Individually, CNRM-CM6-1 was best for precipitation, GFDL-CM4 and NorESM2-MM for Tmax, and FGOALS-g3 and MRI-ESM2-0 for Tmin. While seasonal patterns were well captured historically, Tmin was consistently overestimated. Future projections indicate steady warming, with Tmin rising more rapidly than Tmax. Under SSP5-8.5 by mid-century, Tmax is projected to increase by 1.8°C (6.7%) and Tmin by 1.8°C (15.0%). Precipitation may increase by 11.1% (5.4 mm), though seasonal shifts are notable, including a > 60% March decline and > 120% November increase. These findings emphasize the need for localized climate projections to support resilient development planning. Earth and environmental sciences/Climate sciences Earth and environmental sciences/Environmental sciences Earth and environmental sciences/Ocean sciences Climate Change CMIP6 model climate projections Genale Dawa River Basin Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 04 Dec, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 31 Jul, 2025 Reviews received at journal 31 Jul, 2025 Reviewers agreed at journal 30 Jul, 2025 Reviews received at journal 17 Jul, 2025 Reviewers agreed at journal 10 Jul, 2025 Reviewers agreed at journal 09 Jul, 2025 Reviewers agreed at journal 09 Jul, 2025 Reviewers agreed at journal 09 Jul, 2025 Reviewers invited by journal 08 Jul, 2025 Editor assigned by journal 06 Jul, 2025 Editor invited by journal 10 Jun, 2025 Submission checks completed at journal 10 Jun, 2025 First submitted to journal 28 May, 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. 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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-6764974","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":462891580,"identity":"7d36ead8-9c7b-4735-a7ce-7d2a7dccd66c","order_by":0,"name":"Fetene Muluken Chanie","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4ElEQVRIiWNgGAWjYBAC9gYog4+B+QCQkpAhqIXnADOEwcbAlgDSwkOKFh4DsABhLez9Bx8XVGxLbGPv+fzqRo0FDwP74aMb8GrhOcxsPOPM7cQ2nrPbrHOOAR3Gk5Z2A58We4lkNmneNqAWidxtxjlsQC0SPGZ4tfDIP2b/zfsPqEX+zTPjnH/EaJFgZmPmbQDZwsP8OLeNGC08ycbSPMduG7fxpJkx5/ZJ8LAR8gsP+8GHn3lqbsv2sx9+/DnnW50cP/vhY3i1IAM2CTBJrHIQYP5AiupRMApGwSgYOQAACFFBrRtSHbAAAAAASUVORK5CYII=","orcid":"","institution":"","correspondingAuthor":true,"prefix":"","firstName":"Fetene","middleName":"Muluken","lastName":"Chanie","suffix":""}],"badges":[],"createdAt":"2025-05-28 06:53:18","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6764974/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6764974/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-29498-x","type":"published","date":"2025-12-04T15:58:27+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":97724470,"identity":"2ee54af7-43d4-4812-980b-1a16a59cd33b","added_by":"auto","created_at":"2025-12-08 16:12:27","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3620712,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6764974/v1_covered_d3ab62cc-96a9-41b2-8301-9966c8f79f38.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Evaluation of CMIP6 Model Performance and Future Climate Projections over the Genale Dawa River Basin, Ethiopia","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"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},"keywords":"Climate Change, CMIP6 model, climate projections, Genale Dawa River Basin","lastPublishedDoi":"10.21203/rs.3.rs-6764974/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6764974/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe Genale Dawa River Basin (GDRB) in southeastern Ethiopia is highly vulnerable to climate variability. Yet, limited research has assessed how well the latest CMIP6 climate models simulate key variables in this complex, data-scarce region, posing challenges for effective climate risk assessment and adaptation planning. This study evaluates the performance of 12 CMIP6 Global Climate Models (GCMs) in simulating historical precipitation, maximum temperature (Tmax), and minimum temperature (Tmin) over the GDRB for the baseline period 1985\u0026ndash;2014. Future projections are also assessed for 2021\u0026ndash;2050 and 2051\u0026ndash;2080 under two emission scenarios: SSP2-4.5 and SSP5-8.5. Observational data from ENACTS and 60 ground-based stations were used to validate model outputs, which were re-gridded to 0.5\u0026deg; \u0026times; 0.5\u0026deg; and bias-corrected using quantile mapping. Model performance was assessed using Mean Bias Error (MBE), Root Mean Square Error (RMSE), Pearson correlation, Taylor Skill Score (TSS), and visual diagnostics. The multi-model ensemble (MME) outperformed individual GCMs, with TSS values of 0.80 for precipitation, 0.98 for Tmax, and 0.99 for Tmin. Individually, CNRM-CM6-1 was best for precipitation, GFDL-CM4 and NorESM2-MM for Tmax, and FGOALS-g3 and MRI-ESM2-0 for Tmin. While seasonal patterns were well captured historically, Tmin was consistently overestimated. Future projections indicate steady warming, with Tmin rising more rapidly than Tmax. Under SSP5-8.5 by mid-century, Tmax is projected to increase by 1.8\u0026deg;C (6.7%) and Tmin by 1.8\u0026deg;C (15.0%). Precipitation may increase by 11.1% (5.4 mm), though seasonal shifts are notable, including a\u0026thinsp;\u0026gt;\u0026thinsp;60% March decline and \u0026gt;\u0026thinsp;120% November increase. 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