We investigate the momentum balance in the surf zone, in a setting which is weakly varying in the alongshore direction. Our focus is on the role of nonlinear advective terms. Using numerical experiments, we find that advection tends to counteract alongshore variations in momentum flux, resulting in more uniform kinematics....
Velocity measurements from drifter GPS records are used in an ensemble-based data assimilation technique to extract the river bathymetry. The method is tested on a deep meandering reach and a shallow braided reach of the Kootenai River in Idaho. The Regional Ocean Modeling System (ROMS) is used to model numerous...
A method is presented for estimating bathymetry in a river, based on observations of depth-averaged velocity during steady flow. The estimator minimizes a cost function that combines known information in the form of a prior estimate and measured data (including measurement noise). State augmentation is used to relate the measured...
A model is presented for the horizontal and vertical diffusion of sand tracer particles by waves and is verified using a reanalysis of the experiments of Miller and Komar (1979, ). In the model, sand particles take random jumps at a rate associated with the wave period but also can...
A new method is introduced for incorporating bathymetric uncertainty into predictions of nearshore and river flows (i.e., unstratified flows primarily forced by pressure and radiation stress gradients). The method involves the use of the ensemble Kalman filter (EnKF) as a parameter estimation scheme, where the parameter to be estimated is...
We investigate, theoretically and experimentally, the problem of modeling depth-integrated (2DH) surf zone circulation on an alongshore-nonuniform natural beach, with waves approaching from an arbitrary angle. An approximate theoretical model is developed, which captures the important effect of advection in the alongshore dynamics, and shows that a nondimensional parameter Re[subscript]s...
Eastern boundary current (EBC) upwelling zones are among the most productive of marine ecosystems globally and have been generalized in terms of their food web structure. Little empirically based evidence exists to suggest that there is any one form of trophic control of EBC systems and, because of logistical constraints,...
The objective of this project was to investigate the performance of three different expansive additives on the hydration properties, volume change, and stress development of Portland cement pastes and concrete.
Cenococcum is a genus of ectomycorrhizal Ascomycota that has a broad host range and geographic distribution. It is not known to produce either meiotic or mitotic spores and is known to exist only in the form of hyphae, sclerotia and host-colonized ectomycorrhizal root tips. Due to its lack of sexual...
A methodology is described for assimilating observations in a steady state twodimensional
horizontal (2‐DH) model of nearshore hydrodynamics (waves and currents),
using an ensemble‐based statistical estimator. In this application, we treat bathymetry as a
model parameter, which is subject to a specified prior uncertainty. The statistical estimator
uses state augmentation...