Environmental controls and nonlinear size dependence of the Ångström exponent over the Tengger Desert

Environmental controls and nonlinear size dependence of the Ångström exponent over the Tengger Desert | 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 Environmental controls and nonlinear size dependence of the Ångström exponent over the Tengger Desert Qinghong Zhao, Siyu Chen, Daizhou Zhang, Feng Wu, Tafeng Hu, Yang Zhou, and 8 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7839014/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract The Ångström exponent (α) is a dimensionless parameter describing the wavelength dependence of aerosol extinction and is commonly used as a proxy for particle size. Conventional parameterizations often assume a monotonic α–size relationship, the nonlinear response of α to particle size variations in arid dust sources remains poorly understood. This study quantifies the nonlinear relationship and its environmental controls using 20 days of high-temporal-resolution, in situ measurements collected directly on the Tengger Desert sand dunes. The results show that α ranged between 1.0 and 1.5, reflecting a persistent fine-particle contribution, but declined sharply to 0.1–0.5 during local dust outbreaks dominated by coarse particles. A polynomial model captured three distinct scattering regimes associated with dune-emitted dust, corresponding to Rayleigh, Mie-transition, and non-selective scattering. Rate analysis further revealed that abrupt coarse-particle enhancements and α reductions were characteristic of dust storm and humid conditions, whereas under arid, low-wind regimes α co-varied positively with coarse-particle fluctuations. Overall, these findings demonstrate that particle-size structure and its climatic modulation over active dunes exert a first-order control on the optical response of α. The study provides a quantitative characterization of the nonlinear regulation of α by particle-size distributions, offering a new framework for linking dust microphysical properties with optical behavior in arid source regions. Ångström exponent Aerosols Dust Particle size Radiative forcing Full Text Supplementary Files SupplementaryMaterials.pdf Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 26 Nov, 2025 Reviewers invited by journal 25 Nov, 2025 Editor invited by journal 20 Oct, 2025 Editor assigned by journal 13 Oct, 2025 First submitted to journal 11 Oct, 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7839014","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":550871910,"identity":"f841ddef-ed17-4c54-8f81-a6d9578b2b4a","order_by":0,"name":"Qinghong Zhao","email":"","orcid":"","institution":"Lanzhou University","correspondingAuthor":false,"prefix":"","firstName":"Qinghong","middleName":"","lastName":"Zhao","suffix":""},{"id":550871911,"identity":"90261073-073b-4457-b35a-9f440bb3c3f5","order_by":1,"name":"Siyu Chen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0UlEQVRIiWNgGAWjYDACCRBhwMDAzw7mMpOgRbKZNC0gXYeJ1cI/u/nYwx8FhxM3H2Z/JsFQYZ3YwH72AH5L7hxLN+YxOJy47TBDmgTDmfTEBp68BLxaDCRyzKQZIFqOSTC2HU5skOAxIKAl/5vkD6CWzc2MbRKM/4jSksMmAXLYBmZmNgnGBiK0SNxIM5PmMUg3nnGYjdkiAeixNp4c/Fr4ZyQ/k/zxx1q2v7394Y0PNUAG+xn8WqAAEo8MCUDMRox6IKgjUt0oGAWjYBSMSAAAtRM+7msHvXUAAAAASUVORK5CYII=","orcid":"","institution":"Lanzhou University","correspondingAuthor":true,"prefix":"","firstName":"Siyu","middleName":"","lastName":"Chen","suffix":""},{"id":550871912,"identity":"fe4a2c4a-d6e1-4498-b7fc-3138721de53c","order_by":2,"name":"Daizhou Zhang","email":"","orcid":"","institution":"Prefectural University of Kumamoto","correspondingAuthor":false,"prefix":"","firstName":"Daizhou","middleName":"","lastName":"Zhang","suffix":""},{"id":550871913,"identity":"ce040a9a-216a-4940-a5a0-35e2a9c52341","order_by":3,"name":"Feng Wu","email":"","orcid":"","institution":"Institute of Earth Environment Chinese Academy of Sciences: Chinese Academy of Sciences Institute of Earth Environment","correspondingAuthor":false,"prefix":"","firstName":"Feng","middleName":"","lastName":"Wu","suffix":""},{"id":550871914,"identity":"e731d0fa-d9a8-4347-8295-fed89810a51e","order_by":4,"name":"Tafeng Hu","email":"","orcid":"","institution":"Institute of Earth Environment Chinese Academy of Sciences: Chinese Academy of Sciences Institute of Earth Environment","correspondingAuthor":false,"prefix":"","firstName":"Tafeng","middleName":"","lastName":"Hu","suffix":""},{"id":550871915,"identity":"57e0b634-7672-4616-8e95-11d89c514e28","order_by":5,"name":"Yang Zhou","email":"","orcid":"","institution":"Ocean University of China","correspondingAuthor":false,"prefix":"","firstName":"Yang","middleName":"","lastName":"Zhou","suffix":""},{"id":550871916,"identity":"3af535a7-1823-427b-9dad-f740f8b4187a","order_by":6,"name":"Khan Alam","email":"","orcid":"","institution":"University of Salzburg","correspondingAuthor":false,"prefix":"","firstName":"Khan","middleName":"","lastName":"Alam","suffix":""},{"id":550871917,"identity":"7f799091-7451-44c4-a6db-e50f8a93dcf6","order_by":7,"name":"Salman Zare","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Salman","middleName":"","lastName":"Zare","suffix":""},{"id":550871918,"identity":"f12feed2-6f2a-4bf2-9929-4e9083d02d16","order_by":8,"name":"Chao Zhang","email":"","orcid":"","institution":"Lanzhou University","correspondingAuthor":false,"prefix":"","firstName":"Chao","middleName":"","lastName":"Zhang","suffix":""},{"id":550871919,"identity":"343bd340-d841-4dd4-aa26-6cbba5bbf6cb","order_by":9,"name":"Shasha Qiao","email":"","orcid":"","institution":"Lanzhou University","correspondingAuthor":false,"prefix":"","firstName":"Shasha","middleName":"","lastName":"Qiao","suffix":""},{"id":550871920,"identity":"3d6027c6-ffc0-4a1c-99c6-4b32df7e8084","order_by":10,"name":"Jiabin Yang","email":"","orcid":"","institution":"Lanzhou University","correspondingAuthor":false,"prefix":"","firstName":"Jiabin","middleName":"","lastName":"Yang","suffix":""},{"id":550871921,"identity":"bd3f11b7-4ea9-4cf2-8c9a-f6a2a617175d","order_by":11,"name":"Shuyang Lin","email":"","orcid":"","institution":"Lanzhou University","correspondingAuthor":false,"prefix":"","firstName":"Shuyang","middleName":"","lastName":"Lin","suffix":""},{"id":550871922,"identity":"12faa79e-b9fd-4ee7-9e07-339004b37a9f","order_by":12,"name":"Shuaiwen Wu","email":"","orcid":"","institution":"Lanzhou University","correspondingAuthor":false,"prefix":"","firstName":"Shuaiwen","middleName":"","lastName":"Wu","suffix":""},{"id":550871923,"identity":"e43439c8-4781-40e5-82c8-5e348c6c9d3b","order_by":13,"name":"Fei Zhou","email":"","orcid":"","institution":"Lanzhou University","correspondingAuthor":false,"prefix":"","firstName":"Fei","middleName":"","lastName":"Zhou","suffix":""}],"badges":[],"createdAt":"2025-10-12 07:37:00","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7839014/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7839014/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":97104947,"identity":"82e3fd53-925d-4c9b-86ca-8b30376b4ffb","added_by":"auto","created_at":"2025-12-01 04:29:45","extension":"xml","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":14686,"visible":true,"origin":"","legend":"","description":"","filename":"asenASEND2500185.xml","url":"https://assets-eu.researchsquare.com/files/rs-7839014/v1/b83568c0e21e87fc6fc8232a.xml"},{"id":97104950,"identity":"85371641-deaa-464d-8acf-4d5e1b443682","added_by":"auto","created_at":"2025-12-01 04:29:45","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":973,"visible":true,"origin":"","legend":"","description":"","filename":"ASEND25001852392.go.xml","url":"https://assets-eu.researchsquare.com/files/rs-7839014/v1/e6d1323d695cacb25ebce0df.xml"},{"id":97104949,"identity":"06c99de9-58e3-4362-b884-8d50406c7ea2","added_by":"auto","created_at":"2025-12-01 04:29:45","extension":"xml","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":830,"visible":true,"origin":"","legend":"","description":"","filename":"ASEND2500185Import.xml","url":"https://assets-eu.researchsquare.com/files/rs-7839014/v1/e106dc4dc48897f8bc2e7d08.xml"},{"id":97145310,"identity":"6d49b43b-182a-4c87-891a-1a2903a7dab8","added_by":"auto","created_at":"2025-12-01 10:13:43","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":909005,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7839014/v1_covered_73aa506f-7bb1-45f0-9cf9-a38bcdd18524.pdf"},{"id":97141645,"identity":"218ea060-7c6d-44a2-99cf-af1c2b412c11","added_by":"auto","created_at":"2025-12-01 10:06:52","extension":"pdf","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":156903,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterials.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7839014/v1/9995939c230e4562a2e52a6e.pdf"}],"financialInterests":"","formattedTitle":"Environmental controls and nonlinear size dependence of the Ångström exponent over the Tengger Desert","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"aerosol-science-and-engineering","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"asen","sideBox":"Learn more about [Aerosol Science and Engineering](https://link.springer.com/journal/41810)","snPcode":"41810","submissionUrl":"https://www.editorialmanager.com/asen/default2.aspx","title":"Aerosol Science and Engineering","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Ångström exponent, Aerosols, Dust, Particle size, Radiative forcing","lastPublishedDoi":"10.21203/rs.3.rs-7839014/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7839014/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"The Ångström exponent (α) is a dimensionless parameter describing the wavelength dependence of aerosol extinction and is commonly used as a proxy for particle size. Conventional parameterizations often assume a monotonic α–size relationship, the nonlinear response of α to particle size variations in arid dust sources remains poorly understood. This study quantifies the nonlinear relationship and its environmental controls using 20 days of high-temporal-resolution, in situ measurements collected directly on the Tengger Desert sand dunes. The results show that α ranged between 1.0 and 1.5, reflecting a persistent fine-particle contribution, but declined sharply to 0.1–0.5 during local dust outbreaks dominated by coarse particles. A polynomial model captured three distinct scattering regimes associated with dune-emitted dust, corresponding to Rayleigh, Mie-transition, and non-selective scattering. Rate analysis further revealed that abrupt coarse-particle enhancements and α reductions were characteristic of dust storm and humid conditions, whereas under arid, low-wind regimes α co-varied positively with coarse-particle fluctuations. Overall, these findings demonstrate that particle-size structure and its climatic modulation over active dunes exert a first-order control on the optical response of α. The study provides a quantitative characterization of the nonlinear regulation of α by particle-size distributions, offering a new framework for linking dust microphysical properties with optical behavior in arid source regions.","manuscriptTitle":"Environmental controls and nonlinear size dependence of the Ångström exponent over the Tengger Desert","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-01 04:29:41","doi":"10.21203/rs.3.rs-7839014/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-11-26T05:18:25+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-26T02:52:07+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Aerosol Science and Engineering","date":"2025-10-20T08:45:49+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-13T14:34:08+00:00","index":"","fulltext":""},{"type":"submitted","content":"Aerosol Science and Engineering","date":"2025-10-12T03:36:10+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"aerosol-science-and-engineering","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"asen","sideBox":"Learn more about [Aerosol Science and Engineering](https://link.springer.com/journal/41810)","snPcode":"41810","submissionUrl":"https://www.editorialmanager.com/asen/default2.aspx","title":"Aerosol Science and Engineering","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4a196179-facd-466d-a2d0-6a675dc46ea0","owner":[],"postedDate":"December 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-12-01T04:29:41+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-01 04:29:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7839014","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7839014","identity":"rs-7839014","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}