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...
The nonlinear dynamics of finite amplitude shear instabilities of
alongshore currents in the nearshore surf zone over barred beach topography are
studied using numerical experiments. These experiments extend the recent study
of Allen et al. [1996], which utilized plane beach (constant slope) topography by
including shore-parallel sandbars. The model involves...
A study of swash zone sediment transport was conducted at Gleneden
Beach, Oregon during February 25-28, 1994. The data collected included suspended
sediment concentration (SSC), sea surface elevation, and velocity (initially 4 and 8
cm above the bed) at three cross-shore locations within the swash zone spanning high
tides. Ensemble...
The dynamics of the coastal transition zone off Northern California during late May and early June 1987 art
examined through assimilation modeling studies. A regional baroclinic quasi-geostrophic model is driven by the
data through initial and boundary conditions. These initial and boundary conditions are specified by objective
analysis of hydrographic...
Three‐dimensional circulation in the coastal transition zone (CTZ) off Oregon is
studied using a 3 km resolution model based on the Regional Ocean Modeling System.
The study period is spring and summer 2002, when extensive observations were available
from the northeastern Pacific component of the Global Ocean Ecosystems Dynamics
project....
The generation of an alongshore mean flow by the nonlinear interaction of forced barotropic shelf waves over a continental margin is studied using a wind-forced, ƒ-plane model with bottom friction in an attempt to develop a model for poleward eastern boundary undercurrents. It is assumed that the Rossby number is...
Empirical orthogonal function (EOF) analysis in the frequency domain is extended to complex time series. EOFs are calculated from the eigenvectors of the band-averaged rotary cross-spectral matrix. This gives EOF amplitude and phase for negative and positive frequencies, corresponding to clockwise and anticlockwise rotation for the hodograph model. Rotary EOF...
Previous studies of forced, long continental shelf waves on an ƒ-plane have considered motion on the shelf and slope which is driven by an alongshore component of the wind stress, essentially through the suction of fluid into the surface layer at the coast. These studies have utilized a boundary condition,...
A primitive equation model is used to study the finite-amplitude evolution of instabilities associated with the coastal upwelling front. Simulations of increasing complexity are examined that represent idealizations of summer conditions off the Oregon coast, including cases with steady and with time-variable wind in a domain with alongshore-uniform bathymetry and...
Nonlinear model simulations of a coastal upwelling system show frontal instabilities that initiate at short alongshore scales but rapidly evolve to longer wavelengths. Several factors associated with the nonstationarity of this basic state contribute to the progression in scale. A portion of the system evolution is associated with the external...