Wave-driven currents are a primary driver of sediment transport and morphological change along sandy coastlines. Alongshore currents can be estimated by applying optical retrieval algorithms to remotely sensed imagery. In the present study, the recently updated Optical Current Meter algorithm (OCM V2.0) is applied to optical data from a sandy beach in Duck, NC during a moderate wave energy event. Optically derived current estimates are validated with field sensors throughout the surf zone. A numerical model vertically resolves the wave-driven currents to enhance our understanding of the nearshore circulation. When compared to the surface layer of the modelled alongshore current, the OCM V2.0 estimates yield low mean averaged errors for mean current speeds up to 1 m/s, with the best results yielded in regions of moderate breaking and low vertical current gradient. The algorithm is available in the updated open-access Coastal Imaging Research Network (CIRN) Video-Currents-Toolbox.

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Nearshore Circulation Dynamics Revealed by Combining Optical Observations with Numerical Modelling

  • Elora M. Oades,
  • Katherina Trots,
  • Ryan P. Mulligan

摘要

Wave-driven currents are a primary driver of sediment transport and morphological change along sandy coastlines. Alongshore currents can be estimated by applying optical retrieval algorithms to remotely sensed imagery. In the present study, the recently updated Optical Current Meter algorithm (OCM V2.0) is applied to optical data from a sandy beach in Duck, NC during a moderate wave energy event. Optically derived current estimates are validated with field sensors throughout the surf zone. A numerical model vertically resolves the wave-driven currents to enhance our understanding of the nearshore circulation. When compared to the surface layer of the modelled alongshore current, the OCM V2.0 estimates yield low mean averaged errors for mean current speeds up to 1 m/s, with the best results yielded in regions of moderate breaking and low vertical current gradient. The algorithm is available in the updated open-access Coastal Imaging Research Network (CIRN) Video-Currents-Toolbox.