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Creator:: Wilson, Greg W., Özkan-Haller, H. Tuba, and Holman, Robert A.
Abstract:: 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....
Resource Type:: Article
Full Text:: . Holman (2013), Quantifying the length-scale dependence of surf zone advection, J. Geophys. Res. Oceans

Creator:: Wilson, G. W., Özkan-Haller, H. Tuba, and Holman, R. A.
Abstract:: 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...
Resource Type:: Article
Full Text:: . Holman (2010), Data assimilation and bathymetric inversion in a two‐ dimensional horizontal surf zone

Creator:: Wilson, G. W., Özkan-Haller, H. Tuba, Holman, R. A., Haller, M. C., Honegger, D. A., and Chickadel, C. C.
Abstract:: Bathymetry is a major factor in determining nearshore and surf zone wave transformation and currents, yet is often poorly known. This can lead to inaccuracy in numerical model predictions. Here bathymetry is estimated as an uncertain parameter in a data assimilation system, using the ensemble Kalman filter (EnKF). The system...
Resource Type:: Article
Full Text:: . Holman, M. C. Haller, D. A. Honegger, and C. C. Chickadel (2014), Surf zone bathymetry and circulation

Creator:: Kurapov, Alexander L. and Özkan-Haller, H. Tuba
Abstract:: The impact of assimilation of wave-averaged flow velocities on the bathymetric correction is studied in tests with synthetic (model-generated) data using tangent-linear and adjoint components of a one-way coupled nearshore wave-circulation model. Weakly and strongly nonlinear regimes are considered, featuring energetic unsteady along-beach flows responding to time-independent wave-averaged forcing due...
Resource Type:: Article
Full Text:: Alexander L. Kurapov1 and H. Tuba €Ozkan-Haller1 Received 19 December 2012; revised 1 July 2013; accepted 6

Creator:: Long, Joseph W. and Özkan-Haller, H. Tuba
Abstract:: The rip current field resulting from the transformation of surface gravity waves over offshore submarine canyons is studied. Employing a wave transformation model and a wave-induced circulation model over observed bathymetry we find that wave height variations associated with undulations in the canyon contours cause rip current circulation cells with...
Resource Type:: Article
Full Text:: surf zone from which geophysical properties can be inferred [e.g., Holman et al., 1993; Lippmann and

Creator:: Özkan-Haller, H. Tuba and Li, Ye
Abstract:: We examine the effects of wave-current interaction on the dynamics of instabilities of the surf zone longshore current. We utilize coupled models for the simulation of the incident waves and the wave-induced nearshore circulation. The coupling between the models occurs through radiation stress gradient terms (accounting for the generation of...
Resource Type:: Article

Creator:: Long, J. W. and Özkan-Haller, H. Tuba
Abstract:: urface wave transformation and the resulting nearshore circulation along a section of coast with strong alongshore bathymetric gradients outside the surf zone are modeled for a consecutive 4 week time period. The modeled hydrodynamics are compared to in situ measurements of waves and currents collected during the Nearshore Canyon Experiment...
Resource Type:: Article
Full Text:: channels (dark) [Holman and Stanley, 2007]. The rip cur- rents considered here will not provide the same

Creator:: Long, Joseph W. and Özkan-Haller, H. Tuba
Abstract:: The dynamics of vorticity motions forced by wave groups incident on an alongshore-uniform barred beach are analyzed. For both normally and obliquely incident wave groups, the potential vorticity and enstrophy equations reveal that the temporal variability of wave group–forced vortices is directly linked to the variability in the incoming wave...
Resource Type:: Article

Creator:: Wilson, Greg and Özkan-Haller, H. Tuba
Abstract:: 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...
Resource Type:: Article
Full Text:: vector d contains the measurements, and L is a K 3 M matrix that serves to extract the corresponding

Creator:: Landon, Kyle C., Wilson, Greg W., Özkan-Haller, H. Tuba, and MacMahan, Jamie H.
Abstract:: 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...
Resource Type:: Article
Full Text:: vector d contains K drifter velocity observations. The matrix L is a 3M 3 K mea- surement operator that

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