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dc.rights.licenseopenen_US
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorRODRIGUEZ PADILLA, Isaac
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorCASTELLE, Bruno
IDREF: 087596520
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorMARIEU, Vincent
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorBONNETON, Philippe
IDREF: 059798823
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorMOURAGUES, Arthur
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorMARTINS, Kevin
dc.contributor.authorMORICHON, Denis
dc.date.accessioned2022-10-12T13:06:11Z
dc.date.available2022-10-12T13:06:11Z
dc.date.issued2021-01
dc.identifier.issn2072-4292en_US
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/157673
dc.description.abstractEnThis paper examines the potential of an optical flow video-based technique to estimate wave-filtered surface currents in the nearshore where wave-breaking induced foam is present. This approach uses the drifting foam, left after the passage of breaking waves, as a quasi-passive tracer and tracks it to estimate the surface water flow. The optical signature associated with sea-swell waves is first removed from the image sequence to avoid capturing propagating waves instead of the desired foam motion. Waves are removed by applying a temporal Fourier low-pass filter to each pixel of the image. The low-pass filtered images are then fed into an optical flow algorithm to estimate the foam displacement and to produce mean velocity fields (i.e., wave-filtered surface currents). We use one week of consecutive 1-Hz sampled frames collected during daylight hours from a single fixed camera located at La Petite Chambre d’Amour beach (Anglet, SW France) under high-energy conditions with significant wave height ranging from 0.8 to 3.3 m. Optical flow-computed velocities are compared against time-averaged in situ measurements retrieved from one current profiler installed on a submerged reef. The computed circulation patterns are also compared against surf-zone drifter trajectories under different field conditions. Optical flow time-averaged velocities show a good agreement with current profiler measurements: coefficient of determination (r2)= 0.5–0.8; root mean square error (RMSE) = 0.12–0.24 m/s; mean error (bias) =−0.09 to −0.17 m/s; regression slope =1±0.15; coherence2 = 0.4–0.6. Despite an underestimation of offshore-directed velocities under persistent wave breaking across the reef, the optical flow was able to correctly reproduce the mean flow patterns depicted by drifter trajectories. Such patterns include rip-cell circulation, dominant onshore-directed surface flow and energetic longshore current. Our study suggests that open-source optical flow algorithms are a promising technique for coastal imaging applications, particularly under high-energy wave conditions when in situ instrument deployment can be challenging.
dc.language.isoENen_US
dc.rights.urihttp://creativecommons.org/licenses/by/3.0/
dc.subject.enOptical flow
dc.subject.enRip currents
dc.subject.enSurf zone
dc.subject.enSurface currents
dc.subject.enVideo imagery
dc.title.enWave-Filtered Surf Zone Circulation under High-Energy Waves Derived from Video-Based Optical Systems
dc.typeArticle de revueen_US
dc.identifier.doi10.3390/rs13101874en_US
dc.subject.halSciences de l'environnementen_US
bordeaux.journalRemote Sensingen_US
bordeaux.volume13en_US
bordeaux.hal.laboratoriesEnvironnements et Paléoenvironnements Océaniques et Continentaux (EPOC) - UMR 5805en_US
bordeaux.issue10en_US
bordeaux.institutionUniversité de Bordeauxen_US
bordeaux.institutionCNRSen_US
bordeaux.peerReviewedouien_US
bordeaux.inpressnonen_US
hal.identifierhal-03411135
hal.version1
hal.exportfalse
dc.rights.ccPas de Licence CCen_US
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Remote%20Sensing&rft.date=2021-01&rft.volume=13&rft.issue=10&rft.eissn=2072-4292&rft.issn=2072-4292&rft.au=RODRIGUEZ%20PADILLA,%20Isaac&CASTELLE,%20Bruno&MARIEU,%20Vincent&BONNETON,%20Philippe&MOURAGUES,%20Arthur&rft.genre=article


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