Energy saturation and phase speeds measured on a natural beach

Thornton, Edward B.; Guza, R. T.

doi:10.1029/jc087ic12p09499

Cited by 216 publications

(150 citation statements)

References 26 publications

(12 reference statements)

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“…Thornton and Guza, 1982;Wright et al, 1982;Sallenger and Holman, 1985). The beach face gradient, measured as the gradient between the maximum and minimum shoreline elevation, also may not be the ideal measure in all cases.…”

Section: ˆmentioning

confidence: 99%

Spectral signatures for swash on reflective, intermediate and dissipative beaches

et al. 2014

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In this paper we synthesise a large data set gathered from a wide variety of field deployments and integrate it with previously published results to identify the spectral signatures of swash from contrasting beach types. The field data set includes the full range of micro-tidal beach types (reflective, intermediate and dissipative), with beach gradients ranging from approximately 1:6 to 1:60 exposed to offshore significant wave heights of 0.5 m to 3.0 m.The ratio of swash energy in the short-wave (f>0.05 Hz) to long-wave (f<0.05 Hz) frequency bands is found to be significantly different between the three beach types. Swash energy at short-wave frequencies is dominant on reflective and intermediate beaches and swash at long-wave frequencies is dominant on dissipative beaches; consistent with previously reported spectral signatures for the surf zone on these beach types.The available swash spectra were classified using an automated algorithm (CLARA) into five different classes. The ordered classes represent an evolution in the spectrum shape, described by a frequency downshifting of the energy peak from the short-wave into the longwave frequency band and an increase in the long-wave swash energy level compared to a relatively minor variation in the short-wave swash energy level. A universally common feature of spectra from all beach-states was an 4  f energy roll-off in the short-wave frequency band. In contrast to the broadly uniform appearance of the short-wave frequency band, the appearance of the long wave frequency band was highly variable across the beachstates. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

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Section: ˆmentioning

confidence: 99%

Spectral signatures for swash on reflective, intermediate and dissipative beaches

et al. 2014

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“…To estimate the surfzone width L x , the mean offshore wave conditions were shoaled using linear wave theory (Dean and Dalrymple 1984) to the shoreline using the alongshore-averaged cross-shore beach profile, adjusted for the tidal elevation, with a depth-limited wavebreaking criterion of H s /h $ 0.4 (Thornton and Guza 1982). The cross-shore location of the surfzone boundary X sz is defined as the cross-shore location of the maximum significant wave height H s , and the crossshore location of the shoreline X sh is defined as the cross-shore location where the water depth h, adjusted for the tidal elevation, is zero, with the surfzone width L x 5 X sz 2 X sh .…”

Section: Field Experimentsmentioning

confidence: 99%

Field Observations of Surf Zone–Inner Shelf Exchange on a Rip-Channeled Beach

Brown

MacMahan

Reniers

et al. 2015

Journal of Physical Oceanography

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Cross-shore exchange between the surf zone and the inner shelf is investigated using Lagrangian and Eulerian field measurements of rip current flows on a rip-channeled beach in Sand City, California. Surface drifters released on the inner shelf during weak wind conditions moved seaward due to rip current pulses and then returned shoreward in an arcing pattern, reentering the surf zone over shoals. The cross-shore velocities of the seaward-and shoreward-moving drifters were approximately equal in magnitude and decreased as a function of distance offshore. The drifters carried seaward by the rip current had maximum cross-shore velocities as they exited the surf zone and then decelerated as they moved offshore. The drifters moving shoreward accelerated as they approached the surfzone boundary with maximum cross-shore velocities as they reentered the surf zone over shoals. It was found that Stokes drift was not solely responsible for the onshore transport across the surfzone boundary. The cross-shore diffusivity on the inner shelf was greatest during observations of locally contained cross-shore exchange. These field observations provide evidence that the cross-shore exchange between the surf zone and inner shelf on a rip-channeled beach is due to wave-driven rip current circulations and results in surface material being contained within the nearshore region.

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“…Wave breaking is a function of depth (Thornton and Guza, 1981). Waves break continuously across shoals owing to shallower water depths, and shows up as white in aerial photos or video images owing to foam and bubbles generated during breaking.…”

Section: Introductionmentioning

confidence: 99%