Depth Inversion in the Surf Zone with Inclusion of Wave Nonlinearity Using Video-Derived Celerity

Yoo, Jeseon; Fritz, Hermann M.; Haas, Kevin A.; Work, Paul A.; Barnes, Christopher F.

doi:10.1061/(asce)ww.1943-5460.0000068

Cited by 27 publications

(23 citation statements)

References 25 publications

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“…The traditional approach for estimating the wave celerity c relies in the following estimate:

c \approx Δ x / Δ t

where

Δ x

is the distance travelled by the wave in the time

Δ t

(e.g., see Suhayda & Pettigrew, ). The Radon Transform (Radon, ) has also been used to estimate individual wave celerities in video timestacks by Yoo et al () and then Almar et al (). As these methods can introduce considerable noise, which has a dramatic effect in a modeling exercise, we follow the approach of Tissier et al () which makes use of the high‐resolution character of the data set.…”

Section: Methodsmentioning

confidence: 99%

Energy Dissipation in the Inner Surf Zone: New Insights From LiDAR‐Based Roller Geometry Measurements

et al. 2018

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The spatial and temporal variation of energy dissipation rates in breaking waves controls the mean circulation of the surf zone. As this circulation plays an important role in the morphodynamics of beaches, it is vital to develop better understanding of the energy dissipation processes in breaking and broken waves. In this paper, we present the first direct field measurements of roller geometry extracted from a LiDAR data set of broken waves to obtain new insights into wave energy dissipation in the inner surf zone. We use a roller model to show that most existing roller area formulations in the literature lead to considerable overestimation of the wave energy dissipation, which is found to be close to, but smaller than, the energy dissipation in a hydraulic jump of the same height. The role of the roller density is also investigated, and we propose that it should be incorporated into modified roller area formulations until better knowledge of the roller area and its link with the mean roller density is acquired. Finally, using previously published results from deepwater wave breaking studies, we propose a scaling law for energy dissipation in the inner surf zone, which achieves satisfactory results at both the time‐averaged and wave‐by‐wave scales.

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“…The traditional approach for estimating the wave celerity c relies in the following estimate:

c \approx Δ x / Δ t

where

Δ x

is the distance travelled by the wave in the time

Δ t

Section: Methodsmentioning

confidence: 99%

Energy Dissipation in the Inner Surf Zone: New Insights From LiDAR‐Based Roller Geometry Measurements

et al. 2018

View full text Add to dashboard Cite

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“…Individual waves have been tracked previously in video timestacks (e.g., Yoo et al, 2011), however, the only previous method to track changes in wave height and shape parameters, that is known to the authors, is a method that measured 10 individual waves using a video camera and vertical poles deployed in the surf zone for scale (Suhayda and Pettigrew, 1977). This paper presents a novel method for tracking individual waves across multiple pressure transducers on a cross-shore transect in the surf zone.…”

Section: Introductionmentioning

confidence: 98%

A novel method for tracking individual waves in the surf zone

Power

Hughes

Baldock

2015

Coastal Engineering

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“…In the last decade, remote‐sensing‐based methods have become increasingly popular to monitor coastal evolution [e.g., Holman and Stanley , ]. These methods often rely on the estimation of an average wave celerity from spatially coherent, instantaneous (∼1 Hz) time series of pixel intensity, which is used as a proxy to retrieve water depth [e.g., Stockdon and Holman , ; Yoo et al ., ; Almar et al ., ; Holman et al ., ]. This so‐called depth‐inversion is an interesting alternative to in situ bathymetric surveys, as it, when repeated with time, provides an estimate of bathymetric change over large areas at relatively low cost; however, its accuracy depends crucially on the functional relationship between time‐averaged wave celerity and water depth, that is to say on the choice of the parametrization for the celerity [see Catalán and Haller , , for a review].…”

Section: Introductionmentioning

confidence: 99%

“…Most efforts to improve the prediction of wave celerity have focused on this nonlinear effect. Taking into account the wave height through the use of nonlinear celerity models indeed leads to improved predictions and reduces depth estimation errors in the last stages of shoaling and in the surf zone [ Grilli , ; Catalán and Haller , ; Yoo et al ., ]; however, relatively large discrepancies between time‐averaged measured and nonlinearly predicted celerities still remain in the inner surf zone [ Tissier et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Infragravity‐wave modulation of short‐wave celerity in the surf zone

et al. 2015

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The cross‐shore evolution of individual wave celerity is investigated using two high‐resolution laboratory experiments on bichromatic waves. Individual waves are tracked during their onshore propagation and their characteristics, including celerity, are estimated. The intrawave variability in celerity is low in the shoaling zone but increases strongly after breaking. It is maximum when the infragravity‐wave height to water depth ratio is the largest, that is to say close to the shoreline. There the observed range of individual wave celerity can be as large as the mean celerity value. This variability can be largely explained by the variations in water depth and velocity induced by the infragravity waves. The differences in celerity are such that they lead to the merging of the waves in the inner surf zone for most of the wave conditions considered. Again, the location at which the first waves start merging strongly correlates with the infragravity‐wave height to water depth ratio. The consequences of these findings for celerity‐based depth‐inversion techniques are finally discussed. Surprisingly, accounting for the infragravity‐wave modulation of the velocity field in the celerity estimate does not significantly improve depth estimation in the surf zone. However, it is shown that the occurrence of bore merging decreases significantly the coherence of the wavefield in the surf zone. This loss of coherence could hamper celerity estimation from pixel intensity time series and explain, at least partly, the relatively poor performance of depth‐inversion techniques in the inner surf zone.

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Depth Inversion in the Surf Zone with Inclusion of Wave Nonlinearity Using Video-Derived Celerity

Cited by 27 publications

References 25 publications

Energy Dissipation in the Inner Surf Zone: New Insights From LiDAR‐Based Roller Geometry Measurements

Energy Dissipation in the Inner Surf Zone: New Insights From LiDAR‐Based Roller Geometry Measurements

A novel method for tracking individual waves in the surf zone

Infragravity‐wave modulation of short‐wave celerity in the surf zone

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