A nonlinear model is developed to study the time‐dependent relationship between the alongshore variability of a sandbar, a(t), and alongshore‐averaged sandbar position, xc(t). Sediment transport equations are derived from energetics‐based formulations. A link between this continuous physical representation and a parametric form describing the migration of sandbars of constant shape...
Sandbars are ubiquitous, yet not well understood
beach features that change their position and shape in
response to changing wave conditions. We propose and test
a simple empirical model consisting of two coupled linear
differential equations that represents bar dynamics in terms
of wave forcing and two other state variables:...
Time and length scales of beach variability have been quantified using 16 years
of beach surveys sampled at the Army Corps of Engineers' Field Research Facility,
located on the U.S. Atlantic coast. Between 50% and 90% of the bathymetric variability at
this site was explained by alongshore-uniform response over the...
The nonlinear dynamics of unstable alongshore currents in the nearshore
surf zone over variable barred beach topography are studied using numerical
experiments. These experiments extend the recent studies of Allen et al. [1996]
and Slnn et al. [1998], which utilized alongshore uniform beach topographies by
including sinusoidal alongshore variation to...
We present an optical method (optical current meter) to measure the longshore
component of nearshore surface currents by measuring the alongshore drift of persistent
sea foam in the surf zone. The method uses short time series of video data collected from
an alongshore array of pixels. These space-time data are...
We present an optical method (optical current meter) to measure the longshore
component of nearshore surface currents by measuring the alongshore drift of persistent
sea foam in the surf zone. The method uses short time series of video data collected from
an alongshore array of pixels. These space-time data are...
This repository item contains the files needed to reproduce the results reported in the published work entitled "Runups of unusual size: rogueness and variability of swash" in the Journal of Geophysical Research. As described in the publication, the results described within it pertain to simulations of wave runup for various...
A form of the linear, inviscid shallow water wave equation which includes alongshore uniform, but cross-shore variable, longshore currents and bathymetry is presented. This formulation provides a continuum between gravity waves (either leaky or edge waves) on a longshore current, and the recently discovered shear waves. In this paper we...
A new remote sensing technique based on video image processing
has been developed for the estimation of nearshore bathymetry. The shoreward
propagation of waves is measured using pixel intensity time series collected at a
cross-shore array of locations using remotely operated video cameras. The incident
band is identified, and the...
Recently, models for the onshore migration of nearshore sandbars were improved by including an empirical acceleration term in the sediment transport formulation (Hoefel and Elgar, 2003). Here, field observations of the fluid-sediment interface suggest that the success of this empirical parameter may result from unsteady forcing of sediment beds by...