Surf Zone Waves at the Onset of Breaking: 2. Predicting Breaking and Breaker Type

Abstract

Understanding the dynamics of breaking waves in the surf zone is vital to the progress of nearshore wave and circulation models toward operational use. The goal of wave models in coastal regions is to capture relevant physical processes through explicit representation or field-validated parameterizations. Phase-resolving models, such as Simulating WAves till SHore or SWASH (Zijlema et al., 2011), predict sea surface elevation in space and time, which allows for breaking criteria, critical wave speed or wave steepness to be assessed on a wave-by-wave basis and for wave shape changes to be tracked as breakers develop. A widely used phase-averaged model, Simulating WAves Nearshore or SWAN (Booij et al., 1997), or SWAN, parameterizes energy dissipation due to wave breaking using the Battjes and Janssen (1978) bore model. This bore model determines the portion of the wave height spectra that breaks using the breaker parameter γ = H/h, the ratio of wave height to water depth. Phase-resolving models are often used for basic research on wave mechanics and as input for phase-averaged models, which are larger scale and routinely used to predict and hindcast wave conditions for research and management decisions.Traditionally, γ is estimated as a bulk statistic, using the significant wave height, H sig , or the root-mean-squared wave height, H rms , and the mean water depth, h . For example, Sallenger and Holman (1985) found

The Coastal Imaging Research Network (CIRN)

“…Over the last decade, the advent of smart phones [17][18][19], action [20][21][22], web-based beach and security cameras [23][24][25][26][27], as well as low-cost, highquality optical imaging from UAS have made coastal imaging more accessible [21,28]. The ubiquity of UAS technology has also made low-cost infra-red sensors more accessible for coastal imaging applications [29,30].…”

“…Exploration into the use of wavelengths other than the visible band (e.g., infrared, hyperspectral) and more active sensing approaches (e.g., lidar, x-band radar, synthetic aperture radar (SAR)) must continue, and will likely accelerate with decreasing costs of more sophisticated sensors. For example, 3-dimensional observations of individual breaking waves using lidar have revealed new information on the complex kinematics and geometry of spilling and plunging breakers and propagating bores [29,30,92,93]. Fusion between data sources will likely lead to an improved resolution of processes and better parameterization of those processes in numerical models [29,85].…”

“…For example, 3-dimensional observations of individual breaking waves using lidar have revealed new information on the complex kinematics and geometry of spilling and plunging breakers and propagating bores [29,30,92,93]. Fusion between data sources will likely lead to an improved resolution of processes and better parameterization of those processes in numerical models [29,85]. A multi-modal approach camera calibration has been shown to be effective as well [27].…”

Surf Zone Waves at the Onset of Breaking: 1. LIDAR and IR Data Fusion Methods

“…The skewed Gaussian wave-form fit is also a promising tool for tracking the steepening of a wave prior to breaking. The companion paper (Carini et al, 2021) focuses on the evolution of wave parameters near the onset of breaking and includes analysis of these other slope metrics for steep and nearly overturning spilling and plunging breakers.…”

Surf Zone Turbulence and Suspended Sediment Dynamics—A Review

“…Field data, in particular, notoriously contain measurement inaccuracies, for example, with respect to the elevation above the bed where variables are measured, and the risks of bubble contamination of signals from optical and acoustic sensors. Moreover, robust prediction of wave (breaker) type is still not achievable, although recent efforts [102] represent a step forward in this respect. Some general characteristics have emerged on suspended sediment transport driven by incoming sea/swell waves.…”