Wave-Filtered Surf Zone Circulation under High-Energy Waves Derived from Video-Based Optical Systems
| dc.rights.license | open | en_US |
| hal.structure.identifier | Environnements et Paléoenvironnements OCéaniques [EPOC] | |
| dc.contributor.author | RODRIGUEZ PADILLA, Isaac | |
| hal.structure.identifier | Environnements et Paléoenvironnements OCéaniques [EPOC] | |
| dc.contributor.author | CASTELLE, Bruno
IDREF: 087596520 | |
| hal.structure.identifier | Environnements et Paléoenvironnements OCéaniques [EPOC] | |
| dc.contributor.author | MARIEU, Vincent | |
| hal.structure.identifier | Environnements et Paléoenvironnements OCéaniques [EPOC] | |
| dc.contributor.author | BONNETON, Philippe
IDREF: 059798823 | |
| hal.structure.identifier | Environnements et Paléoenvironnements OCéaniques [EPOC] | |
| dc.contributor.author | MOURAGUES, Arthur | |
| hal.structure.identifier | Environnements et Paléoenvironnements OCéaniques [EPOC] | |
| dc.contributor.author | MARTINS, Kevin | |
| dc.contributor.author | MORICHON, Denis | |
| dc.date.accessioned | 2022-10-12T13:06:11Z | |
| dc.date.available | 2022-10-12T13:06:11Z | |
| dc.date.issued | 2021-01 | |
| dc.identifier.issn | 2072-4292 | en_US |
| dc.identifier.uri | https://oskar-bordeaux.fr/handle/20.500.12278/157673 | |
| dc.description.abstractEn | This 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.iso | EN | en_US |
| dc.rights.uri | http://creativecommons.org/licenses/by/3.0/ | |
| dc.subject.en | Optical flow | |
| dc.subject.en | Rip currents | |
| dc.subject.en | Surf zone | |
| dc.subject.en | Surface currents | |
| dc.subject.en | Video imagery | |
| dc.title.en | Wave-Filtered Surf Zone Circulation under High-Energy Waves Derived from Video-Based Optical Systems | |
| dc.type | Article de revue | en_US |
| dc.identifier.doi | 10.3390/rs13101874 | en_US |
| dc.subject.hal | Sciences de l'environnement | en_US |
| bordeaux.journal | Remote Sensing | en_US |
| bordeaux.volume | 13 | en_US |
| bordeaux.hal.laboratories | Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC) - UMR 5805 | en_US |
| bordeaux.issue | 10 | en_US |
| bordeaux.institution | Université de Bordeaux | en_US |
| bordeaux.institution | CNRS | en_US |
| bordeaux.peerReviewed | oui | en_US |
| bordeaux.inpress | non | en_US |
| hal.identifier | hal-03411135 | |
| hal.version | 1 | |
| hal.export | false | |
| dc.rights.cc | Pas de Licence CC | en_US |
| bordeaux.COinS | ctx_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 |
