A new remote predictor of wave reflection based on runup asymmetry

Almar, Rafaël; Blenkinsopp, Chris; Almeida, Luís Pedro; Catalán, Patricio A.; Bergsma, Erwin W. J.; Cienfuegos, Rodrigo; Viet, Nguyen Trung

doi:10.1016/j.ecss.2018.10.018

Cited by 12 publications

(4 citation statements)

References 72 publications

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“…In addition to morphodynamic-zone studies, the technique can support the use of existing stand-alone automated procedures for coastal image analysis. Specific areas of the image can be previously extracted and/or masked to fasten, for instance, wave breaking height [25,45,46], rip currents [47][48][49][50], shoreline detection [35,[51][52][53][54], wave runup measurements [30,35,[55][56][57][58][59][60][61][62], and intertidal beach topography [28,29,36,61,[63][64][65][66]. The use of the technique can also be coupled to the existing algorithm that focus on beach morphological features detection [67][68][69][70][71] for a fully description of coastal area from coastal imaging.…”

Section: Discussionmentioning

confidence: 99%

Nearshore Wave Transformation Domains from Video Imagery

Andriolo¹

2019

JMSE

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Within the nearshore area, three wave transformation domains can be distinguished based on the wave properties: shoaling, surf, and swash zones. The identification of these distinct areas is relevant for understanding nearshore wave propagation properties and physical processes, as these zones can be related, for instance, to different types of sediment transport. This work presents a technique to automatically retrieve the nearshore wave transformation domains from images taken by coastal video monitoring stations. The technique exploits the pixel intensity variation of image acquisitions, and relates the pixel properties to the distinct wave characteristics. This allows the automated description of spatial and temporal extent of shoaling, surf, and swash zones. The methodology was proven to be robust, and capable of spotting the three distinct zones within the nearshore, both cross-shore and along-shore dimensions. The method can support a wide range of coastal studies, such as nearshore hydrodynamics and sediment transport. It can also allow a faster and improved application of existing video-based techniques for wave breaking height and depth-inversion, among others.

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Section: Discussionmentioning

confidence: 99%

Nearshore Wave Transformation Domains from Video Imagery

Andriolo¹

2019

JMSE

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“…Swash height is defined as the difference between the maximum upwash and the minimum downwash in a complete swash cycle. Significant swash height is the integration of different swash bands and is calculated as follows [36,47]:…”

Section: Infragravity Swash Height Proportionmentioning

confidence: 99%

Laboratory Observations of Swash Signatures Using Video Imagery

Yang

Zhang

Shi

et al. 2022

JMSE

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Swash motions are important for the design and assessment of beach protection projects, while the limitation of insightful observations in the swash zone still exists. An automatic identification method based on video imagery is developed to monitor and extract instantaneous swash motions in the laboratory. The method increases video sampling frequency and improves image enhancement in identification. The improved method fits well with the results of the manual method. The incident band roll-off of the swash spectrum in the experiment is consistent with those observed on natural beaches. Results have shown that on the barred beach, water depths influence the peak frequency in the incident band and cause a multi-peak swash spectrum. A large incident wave period causes a low peak frequency but high peak energy in the swash spectrum. Large incident wave height results in wider energy coupling, making swash to be saturated and more energy in swash energy. The existence of a barred beach promotes swash energy transferring from a high frequency to a low frequency.

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“…Incoming and outgoing wave heights were separated from the directional energy density (representing the variance associated with the defined frequency band and the variation of the incidence angle from the shore-normal direction, see Almar et al, 2014b), following the method described by Sheremet et al (2002) and Almar et al (2018), integrating from the lower to upper cut-off frequency within the gravity-infragravity band (0.02 Hz-0.5 Hz). Swash monitoring using shore-based video was undertaken at 2 Hz during daylight hours at the three experiment sites (Almar et al, 2017(Almar et al, , 2018a. Time series of pixel intensity were sampled along a cross-shore line (Holland and Holman, 1993), to create timestacks in order to measure swash runup spectra (Figure 1) using the method described in Almar et al, (2017).…”

Section: Field Datamentioning

confidence: 99%

“…Despite this, recent observations have shown that saturation can extend to the infragravity band (Ruggiero and Holman, 2004;Senechal et al, 2011) and infragravity waves can be dissipated through breaking (Van Dongeren et al, 2007;de Bakker et al, 2014;Bertin et al, 2018). Observations at very steep beaches show reflection even in the gravity band (Almar et al, 2014;2018a). In the swash zone, several authors (Huntley et al, 1977;Guza and Thornton, 1982;Ruessink et al, 1998) describe a swash spectra saturation roll-off around f 3 (with f the frequency) based on theoretical analysis and observation.…”

mentioning

confidence: 99%