High accuracy river discharge estimation  using UAS-based hydrometry and SWOT-derived WSE            

High accuracy river discharge estimation using UAS-based hydrometry and SWOT-derived WSE | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 10 April 2026 V2 Latest version Share on High accuracy river discharge estimation using UAS-based hydrometry and SWOT-derived WSE Authors : Zhen Zhou 0000-0003-0839-8802 [email protected] , Freja Damgaard Christensen , David Gustafsson , Xinqi Hu , Simon Jakob Köhn , Villads Flendsted Jensen , Michael Andreas Pedersen , … Show All … , Sune Nielsen , Daniel Wennerberg , Viktor Fagerström , Daniel Cendagorta-Galarza , Maria Jose Escorihuela , and Peter Bauer-Gottwein Show Fewer Authors Info & Affiliations https://doi.org/10.22541/au.176348782.27152756/v2 385 views 173 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract River discharge remains critically ungauged across much of the globe, limiting the accuracy of flood forecasting and constraining climate adaptation strategies. To address this, we propose a novel framework that integrates occasional Unoccupied Aerial Systems (UAS) with satellite Earth observations. Specifically, we construct a high-resolution hydraulic model of the Torne River in northern Scandinavia by combining a steady gradually varied flow (SGVF) solver with riverbed geometry extracted from UAS-based water-penetrating radar (WPR). The model is calibrated using four in-situ measured discharge–water surface elevation (WSE) snapshots from the Surface Water and Ocean Topography (SWOT) mission to estimate spatially variable, depth-dependent Manning’s roughness coefficients via automated optimization. This calibration enables river discharge to be estimated solely from satellite altimetry data (e.g., SWOT, Sentinel-3, and ICESat-2). Our approach demonstrates high accuracy and operational feasibility, achieving a mean absolute relative error of only 6.15% when validated against in situ gauge measurements. Remarkably, the model successfully reconstructed an extreme 100-year flood event observed by ICESat-2, with an error of just 2.59%. This framework provides a scalable and transferable approach for accurately estimating river discharge in virtually any reach observable by SWOT, in combination with one-off or occasional UAS hydrometry surveys. Abstract content goes here Supplementary Material File (paper_v2.pdf) Download 3.68 MB Information & Authors Information Version history V1 Version 1 18 November 2025 V2 Version 2 10 April 2026 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords hydraulic modeling manning coefficient swot uas water-penetrating radar Authors Affiliations Zhen Zhou 0000-0003-0839-8802 [email protected] DTU Space, Technical University of Denmark Department of Geosciences and Natural Resource Management, University of Copenhagen View all articles by this author Freja Damgaard Christensen DTU Sustain, Technical University of Denmark View all articles by this author David Gustafsson SMHI Sveriges Meteorologiska och Hydrologiska Institut View all articles by this author Xinqi Hu Chair of Hydrology and River Basin Management, Technical University of Munich View all articles by this author Simon Jakob Köhn DTU Space, Technical University of Denmark View all articles by this author Villads Flendsted Jensen Drone Systems Aps View all articles by this author Michael Andreas Pedersen Drone Systems Aps View all articles by this author Sune Nielsen Drone Systems Aps View all articles by this author Daniel Wennerberg SMHI Sveriges Meteorologiska och Hydrologiska Institut View all articles by this author Viktor Fagerström SMHI Sveriges Meteorologiska och Hydrologiska Institut View all articles by this author Daniel Cendagorta-Galarza Lobelia View all articles by this author Maria Jose Escorihuela isardSAT View all articles by this author Peter Bauer-Gottwein DTU Space, Technical University of Denmark Department of Geosciences and Natural Resource Management, University of Copenhagen View all articles by this author Metrics & Citations Metrics Article Usage 385 views 173 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Zhen Zhou, Freja Damgaard Christensen, David Gustafsson, et al. High accuracy river discharge estimation using UAS-based hydrometry and SWOT-derived WSE . Authorea . 10 April 2026. DOI: https://doi.org/10.22541/au.176348782.27152756/v2 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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