Investigating and quantifying ground effect using spectrograms of realistic aircraft flyover measurements

Investigating and quantifying ground effect using spectrograms of realistic aircraft flyover measurements | 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 Investigating and quantifying ground effect using spectrograms of realistic aircraft flyover measurements Anandini Sravya Jayanthi, Mirjam Snellen, Alireza Amiri-Simkooei This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7291796/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 19 Feb, 2026 Read the published version in CEAS Aeronautical Journal → Version 1 posted You are reading this latest preprint version Abstract par \par This paper proposes a measurement-based methodology for investigating the ground effect observed in real-life aircraft flyover measurements in low-noise regions. An acoustic array is used for obtaining a spectrogram of the sound with ground reflections to a large extent eliminated. By applying a model to account for the ground effect, a semi-synthetic spectrogram is obtained. This spectrogram is then qualitatively compared with the spectrogram obtained from single microphone measurements at two heights to verify whether indeed the semi-synthetic spectrogram agrees with those measured by the single microphones. As a next step, the ground effect for the fly-overs measured is quantified by using the array-recorded signals together with the model for the ground effect for all flyovers. By correcting the single microphone signals for the estimated ground effect improved agreement improved agreement between noise levels at both receiver heights and the array measurements is obtained. For flyovers with higher elevation angles, a greater reduction in noise, up to 2.3 dBA, is observed, despite the larger slant distances. In contrast, flyovers at lower elevation angles show a smaller reduction of approximately 1.8 dBA. This contrasts with the common corrections applied for lateral attenuation in best-practice modelling where the attenuation (accounting for more than only the ground effect) diminishes at higher elevation angles. ground effect phased microphone array flyover measurements low-noise regions Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 19 Feb, 2026 Read the published version in CEAS Aeronautical Journal → 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. 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-7291796","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":509566231,"identity":"a3e8da01-8398-403c-bcda-1857b1716f04","order_by":0,"name":"Anandini Sravya Jayanthi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/0lEQVRIie3PsYrCMBjA8S8E7BLONQ61r5DSwYIWX6Ui6NJHOI5AoS56rr236Hg3mfJBXXyIii/QW45OYlq45aDV8cD8h0BDfvlSAJPpv8bblYGqAIi0SKm//AfIgEGehppQ6srfa/rThLJHyFBaJfiv6EycXY5BjfaeUqskn92EKyaAF+h+JS8hRiF6HzElkpx6HqaYdgMkWcFEQxYZDnNJkm7iKP0wfsV5S3xNDthM6SFCgYBRoi9vCDRT6B3iIhNq9L5eZkUk8u1q7aV6SrroIePj5nzhP9Mgw5NX1bOpvd/EUH0ns+7fpwDIIf6zG3aDNlLB250jJpPJ9NTdALD6VI1RvQ76AAAAAElFTkSuQmCC","orcid":"","institution":"Delft University of Technology","correspondingAuthor":true,"prefix":"","firstName":"Anandini","middleName":"Sravya","lastName":"Jayanthi","suffix":""},{"id":509566232,"identity":"3331711f-f31c-407b-9d7e-61584623bad4","order_by":1,"name":"Mirjam Snellen","email":"","orcid":"","institution":"Delft University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Mirjam","middleName":"","lastName":"Snellen","suffix":""},{"id":509566237,"identity":"ada9772e-a8ed-4cbf-a4fe-d7b920d79b99","order_by":2,"name":"Alireza Amiri-Simkooei","email":"","orcid":"","institution":"Delft University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Alireza","middleName":"","lastName":"Amiri-Simkooei","suffix":""}],"badges":[],"createdAt":"2025-08-04 13:38:25","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7291796/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7291796/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s13272-026-00947-1","type":"published","date":"2026-02-19T15:58:38+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":103251262,"identity":"20e9841d-017f-4c26-a839-4e0b5cd26af8","added_by":"auto","created_at":"2026-02-23 16:07:39","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4962079,"visible":true,"origin":"","legend":"","description":"","filename":"Investigatingandquantifyinggroundeffectusingspectrogramsofrealisticaircraftflyovermeasurements.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7291796/v1_covered_d1f22d21-0660-472e-8e3b-dcc0966dc828.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Investigating and quantifying ground effect using spectrograms of realistic aircraft flyover measurements","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"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":"ground effect, phased microphone array, flyover measurements, low-noise regions","lastPublishedDoi":"10.21203/rs.3.rs-7291796/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7291796/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003epar \\par This paper proposes a measurement-based methodology for investigating the ground effect observed in real-life aircraft flyover measurements in low-noise regions. An acoustic array is used for obtaining a spectrogram of the sound with ground reflections to a large extent eliminated. By applying a model to account for the ground effect, a semi-synthetic spectrogram is obtained. This spectrogram is then qualitatively compared with the spectrogram obtained from single microphone measurements at two heights to verify whether indeed the semi-synthetic spectrogram agrees with those measured by the single microphones. As a next step, the ground effect for the fly-overs measured is quantified by using the array-recorded signals together with the model for the ground effect for all flyovers. By correcting the single microphone signals for the estimated ground effect improved agreement improved agreement between noise levels at both receiver heights and the array measurements is obtained. For flyovers with higher elevation angles, a greater reduction in noise, up to 2.3 dBA, is observed, despite the larger slant distances. 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