Observations of runup and energy flux on a low-slope beach with high-energy, long-period ocean swell

Citation:
Fiedler, JW, Brodie KL, McNinch JE, Guza RT.  2015.  Observations of runup and energy flux on a low-slope beach with high-energy, long-period ocean swell. Geophysical Research Letters. 42:9933-9941.

Date Published:

2015/11

Keywords:

climate, dissipation, infragravity waves, intermediate, motions, nearshore, setup, Surfzone, swash oscillations, variability

Abstract:

The transformation of surface gravity waves from 11 m depth to runup was observed on the low-sloped (1/80) Agate Beach, Oregon, with a cross-shore transect of current meters, pressure sensors, and a scanning lidar. Offshore wave heights H-0 ranged from calm (0.5 m) to energetic (> 7 m). Runup, measured with pressure sensors and a scanning lidar, increases linearly with (H0L0)(1/2), with L-0 the deep-water wavelength of the spectral peak. Runup saturation, in which runup oscillations plateau despite further increases in (H0L0)(1/2), is not observed. Infragravity wave shoaling and nonlinear energy exchanges with short waves are included in an infragravity wave energy balance. This balance closes for high-infragravity frequencies (0.025-0.04 Hz) but not lower frequencies (0.003-0.025 Hz), possibly owing to unmodeled infragravity energy losses of wave breaking and/or bottom friction. Dissipative processes limit, but do not entirely damp, increases in runup excursions in response to increased incident wave forcing.

Notes:

n/a

Website

DOI:

10.1002/2015gl066124