Turbulent diffusion and volcanic gas dispersion in the Atmospheric Surface Layer: Insights from La Solfatara, Campi Flegrei, Italy

Turbulent diffusion and volcanic gas dispersion in the Atmospheric Surface Layer: Insights from La Solfatara, Campi Flegrei, Italy | 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 Turbulent diffusion and volcanic gas dispersion in the Atmospheric Surface Layer: Insights from La Solfatara, Campi Flegrei, Italy Silvia Massaro, Antonio Costa, Manuel Stocchi, Giovanni Macedonio, and 10 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6131117/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Sep, 2025 Read the published version in Earth, Planets and Space → Version 1 posted 5 You are reading this latest preprint version Abstract Numerical models are widely used to simulate volcanic gas dispersion and estimate local emission sources. However, significant uncertainties arise from the approximations inherent in their physical formulations. Recent advances in high-performance computing (HPC) have enabled high-resolution simulations with minimal numerical diffusion, revealing previously unnoticed limitations in the Monin-Obukhov Similarity Theory used within atmospheric gas dispersion models. One key issue is the determination of the minimum vertical turbulence diffusion coefficient ( Kz min ) in the Atmospheric Surface Layer (ASL), which plays a crucial role in reducing biases in advection-diffusion models caused by inadequate turbulence representation. In this study, we refine the Eulerian passive gas transport model DISGAS (v. 2.5.1) using measured data on fumarolic and diffuse CO₂ fluxes and air concentrations, along with local wind measurements collected during an ad hoc field campaign from 4–10 May 2023. To account for uncertainties in gas flow rates and turbulent velocity fluctuations, we conducted a statistically robust set of simulations by varying CO₂ fluxes and Kz min values. Model outputs were compared with in situ CO₂ concentration measurements at fixed monitoring stations. Results indicate that during stable atmospheric conditions, setting Kz min within the range of 1.5–2 m² s − 1 significantly improves agreement with observations and reduces systematic biases in source estimation. These findings refine model parameterization to better represent turbulence under stable atmospheric conditions at La Solfatara crater during the May 2023 survey. Moreover, the proposed methodology can be adopted for automated data assimilation workflows aimed at constraining unknown fumarolic gas source fluxes in other volcanic settings. Gas dispersion model Carbon Dioxide Diffusivity coefficient Atmospheric turbulence Full Text Supplementary Files Additionalfiles.pdf graphicalabatract.png Cite Share Download PDF Status: Published Journal Publication published 16 Sep, 2025 Read the published version in Earth, Planets and Space → Version 1 posted Editorial decision: Major Revision 27 May, 2025 Reviewers agreed at journal 20 Mar, 2025 Reviewers invited by journal 10 Mar, 2025 Editor assigned by journal 05 Mar, 2025 First submitted to journal 28 Feb, 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. 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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-6131117","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":431605585,"identity":"b1181ace-1bf4-43f1-9931-003da8a66010","order_by":0,"name":"Silvia 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Model outputs were compared with in situ CO₂ concentration measurements at fixed monitoring stations. Results indicate that during stable atmospheric conditions, setting \u003cem\u003eKz\u003c/em\u003e\u003csub\u003e\u003cem\u003emin\u003c/em\u003e\u003c/sub\u003e within the range of 1.5\u0026ndash;2 m\u0026sup2; s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e significantly improves agreement with observations and reduces systematic biases in source estimation.\u003c/p\u003e \u003cp\u003eThese findings refine model parameterization to better represent turbulence under stable atmospheric conditions at La Solfatara crater during the May 2023 survey. 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