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Lookup NU author(s): Harley Dixey, Professor Stuart DunningORCiD, Dr Matthew PerksORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Image velocimetry (IV) methods for measuring river flow have gained significant attention, with growing interest in satellite imagery applications. Despite this potential, challenges exist in identifying surface features critical for IV at the coarser spatial resolutions of satellite imagery (1–3 m px−1), compared to near-field imagery (e.g. uncrewed aerial systems). Here we evaluate IV performance across resolutions ranging from 0.02 to 3 m px−1, examining the surface features required for successful Satellite IV (SIV). Results indicate that IV accuracy depends on scene characteristics, with high-contrast, well-distributed surface tracers essential at coarse resolutions. Using suitable scenes with spatial resolutions up to 3 m px−1, discharge estimates are comparable to both original-resolution results and reference data (± 5%). This study demonstrates the viability of SIV using 1 second image pairs and, provided that sufficient trackable surface features are present, highlights its potential to support river discharge monitoring, particularly in remote or ungauged regions.
Author(s): Dixey HT, Rollanson E, Dunning S, Perks MT
Publication type: Article
Publication status: Published
Journal: Hydrological Sciences Journal
Year: 2026
Volume: 71
Issue: 4
Pages: 784-801
Online publication date: 29/01/2026
Acceptance date: 30/09/2025
Date deposited: 03/02/2026
ISSN (print): 0262-6667
ISSN (electronic): 2150-3435
Publisher: Taylor & Francis
URL: https://doi.org/10.1080/02626667.2025.2580574
DOI: 10.1080/02626667.2025.2580574
Data Access Statement: The input UAS videos and aDcp data used for these analyses can be found in Engel et al. (2022). The version of KLT-IV used for analysis can be found in Perks (2024). Code used for processing UAS videos data used in the production of figures can be found in Dixey (2025). Planet data are not openly available as Planet is a commercial company; however, access to these data is possible as part of their education and research programme (https://www.planet.com/markets/education-and-research/).
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