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...
The finite amplitude nonlinear behavior of the coastal transition zone (CTZ) jet, assumed to be governed by quasi-geostrophic dynamics, is studied utilizing numerical experiments in an idealized geometry. Finite difference solutions to initial value problems are obtained for a stratified, six-layer fluid in a periodic, flat bottom, f plane channel....
We simulated the erosion and accretion of a natural beach using a wave-resolving
eddy-diffusive model of water and suspended sediment motion in the bottom boundary
layer. Nonlinear advection was included in this one-dimensional (vertical profile) model
by assuming that waves propagated almost without change of form. Flows were forced by...
The sensitivity of model-produced time-dependent wind-driven circulation on the
continental shelf to the turbulent closure scheme employed is studied with a twodimensional
approximation (variations across-shelf and in depth) using the Princeton
Ocean Model. The level 2.5 Mellor-Yamada closure (MY), k-ε closure, and K-Profile
Parameterization schemes are used to evaluate the...
An Eulerian analysis for wave forcing of three-dimensional (3D) wave-averaged mean
circulation in the surf zone is presented. The objective is to develop a dynamically
consistent formulation for applications in a 3D primitive equation model. The analysis is
carried out for the case of shallow-water linear waves interacting with wave-averaged...
An inertial subrange was found in spectra calculated from vertical profiles of temperature gradient recorded in the bottom boundary layer of the Oregon shelf. Spectra were calculated for 53-cm vertical segments. An ensemble average of those spectra that were fully resolved and had high Cox number was compared to the...
Tests of a formula derived for the cutoff wave number of vertical temperature gradient spectra, using
data taken in the upper layers of the North Pacific, show encouraging results. To derive this formula, the
cutoff wave number is assumed to be the Batchelor wave number, with kinetic energy dissipation calculated...
A test of the scaling of the extent of the thinnest vertical temperature gradients, in the near-bottom
boundary layer on the Oregon shelf, shows that the Batchelor wave number determines the cutoff wave
number in vertical temperature gradient spectra. In combination with previous results, in other words,
this test shows...
Model studies of two-dimensional, time-dependent, wind-forced, stratified downwelling circulation on the continental shelf have shown that the near-bottom offshore flow can develop time- and space-dependent fluctuations involving spatially periodic separation and reattachment of the bottom boundary layer and accompanying recirculation cells. Based primarily on the observation that the potential vorticity...
The study of intermediate models for barotropic continental shelf and slope flow fields initiated in Parts I and II is continued. The objective is to investigate the possible use of intermediate models for process and data assimilation studies of nonlinear mesoscale eddy and jet current fields over the continental shelf...