A wave-by-wave forecasting system is desired for optimization of wave energy conversion devices and for improving safety of vessel-based marine operations. This study outlines the first validation attempts of a recently developed forecasting system called Wavecast. The forecasting approach uses X-Band marine radar images for data assimilation, then reconstructs and...
Understanding the past, present, and future behavior of our nation's shorelines is vital for sensible coastal management. Localized areas of erosion, termed "erosional hot spots", can shift the shoreline landward threatening coastal infrastructure (Kraus and Galgano, 2001; Stauble and Gravens, 2004; McNinch, 2004). One specific type of erosional hot spot...
This dissertation has focused on the charateristics of bubbles generated by breaking waves and the feedback of wave-current interaction on the forcing mechanism of low frequency wave especially basin seiching wave. For the first study, Optical image capture observations of breaking waves in a laboratory surf zone are presented. The...
Forecasting of ocean waves over a short duration on the order of tens of seconds was approached with the optimization of wave energy conversion in mind. This study outlines the development of an artificial neural network model, specifically the Nonlinear Autoregressive Network with Exogenous Input (NARX), to predict a wave-by-wave...
Wave breaking in the surf zone is an important forcing
mechanism on the generation of nearshore currents and in the driving
of sediment transport. At the same time, wave breaking can have
significant spatial and temporal variability that needs to be
accounted for in the description of nearshore processes. Remote...
This work investigates a methodology for estimating the ocean stratification gradient based on high-resolution, in space and time, remote sensing observations of internal wave propagation speeds. The internal wave speed observations were collected using a shore-based, X-band marine radar and the ocean vertical density profiles were collected simultaneously from an...
Rip currents pose a serious danger to visitors of bathing beaches; they are also an important process in surf zone circulation. Haller et al. [2014] demonstrated that shore-based X-band radar can be used to compliment in situ measurements of rip currents. However, little is known of the underlying radar imaging...
Radiation stresses, defined as the excess flow of momentum due to the presence of waves (Longuet-Higgins, 1964), are the main drivers behind the cross-shore and longshore forcing that results in wave setup, set-down, and longshore currents (e.g. Svendsen, 2006). Longshore currents entrain and transport sediment and therefore play an important...
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MerrickC. Haller
Radiation stresses, defined as the excess flow of momentum due to the
Oregon State University conducted a series of laboratory experiments to measure and quantify the near-field wave effects caused within arrays of Wave Energy Converters (WEC). As the waves and WECs interact, the WECs generate radiated waves; these effects vary with the location within the array. Analyzing the near-field waves will...
This thesis investigates the effects of wave energy converters (WECs) on water waves through the analysis of extensive laboratory experiments, as well as subsequent numerical simulations. Data for the analysis was collected during the WEC-Array Experiments performed at the O.H. Hinsdale Wave Research Laboratory at Oregon State University, under co-operation...
This dissertation focuses on two core aspects of remote sensing: (a) interpretation of the remotely sensed data to identify and characterize sea surface features of interest, and (b) the quantitative analysis of previously characterized features to produce robust estimates of geophysical variables. Specifically, these aspects are addressed in the context...
The coastal region is home to many types of surface fronts that exist on a submesoscale (1-10 $km$). While in situ observations capture point or transect observations of frontal behavior subsurface, their complex spatial patterns can be well-captured using remote sensing techniques, which provide synoptic views of the ocean surface...
The use of remote sensing techniques in coastal science and engineering has rapidly increased in the past few decades. This dissertation outlines new remote sensing tools using two remote sensing technologies (lidar and X-band marine radar) along with two nearshore hydrodynamic and morphodynamic analyses supported or motivated by these remote...
The characterization of bathymetry and its time evolution is very important for both oceanographic science applications, and for societal reasons relating to coastal engineering
and development. Historically, the process of depth surveying has been costly and labor-intensive.
This is especially true in nearshore regions, hence a method that is both...
This project utilized both shore-based and shipboard commercial marine radar technology to collect wave statistics. In the first application a shore-based system was installed at Yaquina Bay in Newport, Oregon in order to collect real-time wave information. This information was collected under the auspices of the Northwest Association of Networked...
Steep bathymetric anomalies in the beach profile, such as offshore borrow pits, submerged breakwaters, and nearshore canyons can significantly transform the wave climate through the effects of refraction, diffraction, and reflection. When located in the nearshore region the modified wave climate can also substantially change the location of breaking and...
Successful prediction of nearshore sediment migration is important in determining the vulnerability of a coastline. During energetic wave climates (storm events) sediment rapidly erodes from beaches and is deposited offshore. In subsequent milder wave conditions, the sediment migrates shoreward, accreting on the beach and helping to protect the coastline. It...
The ocean deployment of arrays of Wave Energy Converters (WEC arrays) appears likely in the near future, and deployment of offshore wind turbines has already started. These technologies tap into a potential renewable energy resource but also involve complex systems with uncertain environmental consequences that will likely scale with the...
This article was originally published online and in print with an incorrect version of Fig. 1. AIP apologizes for this error. All online versions of the article have been corrected.
Models for surface gravity wave propagation in the presence of currents often assume the current field to be quasi-stationary, which implies that the absolute wave frequency is time invariant. However, in the presence of unsteady currents or time-varying water depth, linear wave theory predicts a time variation of the absolute...
Geospatial data analysis is a multifaceted discipline encompassing the collection, processing, and visualization of diverse datasets. It models and delineates the interactions of people, objects, and phenomena within geographical spaces and predicts patterns based on the relationships between different locations. Despite significant advancements in geospatial data engineering and analytics over...
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MerrickC. Haller
Geospatial data analysis is a multifaceted discipline encompassing
In the presence of strong winds, ocean surface waves dissipate significant amounts of energy by breaking. Here, breaking rates and wave-following turbulent dissipation rate measurements are compared with numerical WAVEWATCH III estimates of bulk energy dissipation. At high winds, the measurements suggest that turbulent dissipation becomes saturated, however the modeled...
During four cruises in July and September of 2008 and 2009, the shipboard X-band radar was tuned to detect the modulated bands of surface roughness caused by converging and diverging currents associated with high-frequency nonlinear internal wave (NLIW) packets. The data collected was used to quantify the propagation direction (ϴp),...
Synthetic-aperture radar (SAR) imagery can provide wavenumber and frequency data to generate bathymetry estimates for locations where limited access or extreme ocean conditions can make standard bathymetry survey techniques difficult or impossible. The availability of SAR data could allow for regular bathymetry estimates of navigational channels providing insight into dredging...
In this study, the effects of implementing different wind input or physics packages in a numerical wave model to recreate large wave conditions are explored. Three large wave events are simulated with WaveWatch III. The wind inputs which are compared are NCEP's Global Forecasting System (GFS) with 0.5 degree resolution...
The optical intensity signals from surf zone waves in a laboratory flume are analyzed using several different phase‐averaging techniques, and a methodology is developed for estimating wave roller lengths and local wave dissipation. The intensity signals (i.e., phase‐averaged intensity profiles) of individual breaking waves are compared with the wave profiles...
A laboratory experiment involving rip currents generated on a barred beach with periodic rip channels indicates that rip currents contain energetic low-frequency oscillations in the presence of steady wave forcing. An analytic model for the time-averaged flow in a rip current is presented and its linear stability characteristics are investigated...
An alternative metric for assessing nearshore hydrodynamic impact due to Wave Energy Converter (WEC) arrays is presented that is based on the modeled changes in alongshore radiation stress gradients in the lee of the array. The metric is developed using a previously observed relationship between measured radiation stresses and alongshore...
The mouth of the Columbia River (MCR) has a longstanding reputation of hazardous navigational conditions. This reputation has been developing since the first ship, the Columbia, traversed through the inlet in 1792. The hazardous conditions are related to the large waves and strong tidal currents that are common in the...
A new set of data from a large-scale sand bar migration experiment is presented. During this experiment, two sandbars were generated. One of the bar was generated by the action of undertow, and sediment moved offshore. The other bar was generated by the shoreward movement of sediment coming from the...
This study presents a methodology for power take off (PTO) forecasting for an array of heave wave energy converters (WECs). Based on spectral data obtained directly from the National Data Buoy Center, representative realistic sea states are generated at the location of the WECs, and by using two wave-structure interaction...
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H. Tuba Özkan-Haller
This study presents a methodology for power take off (PTO) forecasting
Knowledge of wave conditions in nearshore regions supports the development of
ocean wave energy technology by providing wave climatology for device design
considerations, and power output estimates. By modeling wave transformation
over the continental shelf, wave conditions were predicted in nearshore regions
where potential wave energy conversion sites are located....
A Finite Element Model of a deployed Fiber-Optic Micro Cable (FOMC) was performed using the marine cable modeling software, OrcaFlex. The focus of this study was a parametric analysis of a two-part, towed cable array with the FOMC dragged behind a depressor and connected to a drogue chute. Length-to-diameter ratios...
This thesis presents the details of a large-scale laboratory experiment to study the
turbulence generated by waves breaking on a fixed barred beach. The data set includes
comprehensive measurements of free surface displacement and fluid velocity for one
random and one regular wave case.
Observations of the time-averaged turbulent kinetic...
In the northwestern Gulf of Mexico there is a need for reliable water level forecasts to facilitate safe commercial navigation, marine construction, and emergency management. Though the low amplitude tides of the region can be predicted with conventional harmonic techniques, frequent strong storms make accurate forecasts of water levels difficult....
Hydrodynamic models are used as a diagnostic tool to understand the temporal variability of shallow-water processes that are difficult to completely resolve with traditional field measurements. For all simulations, modeled quantities are qualitatively or quantitatively compared with available measurements to gain confidence in conclusions derived from the modeled results. In...
The eventual deployment of wave energy converters (WECs) on a commercial scale will necessitate the grouping of devices into arrays or "wave farms," in order to minimize overhead costs of mooring, maintenance, installation, and electrical cabling for shoreward power delivery. Closely spaced WECs will interact hydrodynamically through diffracted and radiated...
Coastal foredunes protect lives, infrastructure, and ecosystems during severe winter storms. In the U.S. Pacific Northwest (PNW), coastal foredune geomorphology is determined by both physical and ecological mechanisms. Before the 1900's, the native plant Elymus mollis was the dominant dune grass and dune morphology was largely determined by sediment supply...
With energy prices rising and increasing concern about the influence of fossil fuels on climate change, wave energy systems are on the verge of commercial implementation. These first generation wave energy converters utilize either pneumatics or hydraulics to convert the mechanical energy of waves into electricity. For the last several...
Physical modelling is instrumental to the progression of coastal engineering research and our understanding of the offshore and nearshore environments. Scaled models are designed and built to be tested in coastal research laboratories, where a wave basin or flume generates the desired wave conditions for experimentation. The surrounding hydrodynamics of...
Wave and current measurements are presented from a set of laboratory experiments
performed on a fixed barred beach with periodically spaced rip channels using a range of
incident wave conditions. The data demonstrate that the presence of gaps in otherwise
longshore uniform bars dominates the nearshore circulation system for the...
The focus of the paper is the analysis of the flow in rip current systems generated by
channels in longshore bars on a beach. The horizontal variations of rip current systems are
described through the use of the quasi-three-dimensional nearshore circulation model
SHORECIRC. Model predictions are compared to laboratory measurements...
The microwave backscatter properties of surf zone waves are analyzed using field observations.
By utilizing a preexisting, independent, water surface discrimination technique, the microwave returns were
extracted along individual waveforms and the data from shoaling (steepening) waves, surf zone breaking
waves, and remnant foam were separated and quantified. In addition,...
Synchronous and colocated optical and microwave
signals from waves in the surf zone are presented and analyzed.
The field data were collected using a high-resolution video system
and a calibrated horizontally polarized marine radar during the
decaying phase of a storm. The resulting changes in the received
signals from varying...
We review several approaches that have been used to estimate ocean surface gravity wavenumbers from wave-resolving remotely sensed image sequences. Two fundamentally different approaches that utilize these data exist. A power spectral density approach identifies wavenumbers where image intensity variance is maximized. Alternatively, a cross-spectral correlation approach identifies wavenumbers where...
Integrated manufacturing systems, a combination of subtractive, additive, and joining processes, provide a competitive advantage for manufacturing organizations. As product designs become more complex and capital more scarce, an ideal combination of advanced manufacturing technologies (e.g., powder bed fusion or friction welding), in tandem with traditional subtractive manufacturing systems, can...
Wave-induced circulation is the defining characteristic of the nearshore. Within this region, the constant feedback cycle between incoming waves, wave-generated currents, and the mobile sediment bed is responsible for the evolution of complex patterns in nearshore and beach morphology. Central to our understanding of this system is knowledge of the...
Waves are the primary input of energy in the nearshore region, and together with the currents forced through the transfer of momentum that occurs during the wave breaking process they are the principal mechanism for sediment transport in the nearshore. The basic physics of waves and currents are thought to...
In this study, we use a time domain numerical model based on the fully nonlinear extended Boussinesq equations [Wei et al., 1995] to investigate surface wave transformation and breaking-induced nearshore circulation. The energy dissipation due to wave breaking is modeled by introducing an eddy viscosity term into the momentum equations,...
The time and space variability of wave transformation through a tidal inlet is investigated with radar remote sensing. The frequency of wave breaking and the net wave breaking dissipation at high spatial resolution is estimated using image sequences acquired with a land-based X-band marine radar. Using the radar intensity data,...
The design of high-performance, high-speed clock generation and distribution becomes challenging in terms of phase noise, jitter and power consumption, due to the fast development of communication and computing systems. Injection locking is a promising clocking technique since it can significantly improve the energy efficiency, suppress the phase noise of...
Reactor modeling is largely limited by the computational time required to perform accurate full core calculations. There are many different methods and techniques employed in different reactor simulation codes, but properly modeling all of the physics that takes place in the system requires extensive computational effort. The Coarse Mesh Finite...
The Experimental Advanced Airborne Research Lidar ‐ B (EAARL‐B), which was built and deployed by the U.S. Geological Survey (USGS) in 2014, is a novel topographic‐bathymetric lidar system. While retaining a number of features that were pioneered in the original National Aeronautics and Space Administration (NASA) EAARL system (e.g., low...
Underwater robots beneath ocean waves can benefit from feedforward control to reduce position error. This thesis proposes a method using Model Predictive Control (MPC) to predict and counteract future disturbances from an ocean wave field. The MPC state estimator employs a Linear Wave Theory (LWT) solver to approximate the component...
This dissertation primarily uses observations made during the 2005 Kashmir earthquake relief effort and available disaster literature to address problems that impede effective and efficient disaster preparedness and response. Three manuscripts form the body of the dissertation. The manuscripts are thematically linked through the Emergency Management Cycle. Each manuscript examines...
The coast of Oregon is highly dynamic, with beach and dune morphodynamics constantly evolving in response to physical and ecological forcing at scales ranging from seconds to decades and meters to tens of kilometers. Evaluating spatial and temporal trends in shoreline evolution is paramount in understanding and eventually developing a...
The ultimate goal of this work is to analyze and compare two predictive models of thermal profile in laser processing of materials. An analytical method that uses closed-form equations to represent a geometric model of a laser heat source will be contrasted with a commercial computational fluid dynamics code that...
Fluid-structure interaction (FSI) is a very interesting and challenging multi-disciplinary field involving interaction of a movable or deformable structure with an internal or surrounding fluid flow. FSI plays a pivotal role in many different types of real-world situations and practical engineering applications involving large structural deformation and material or geometric...
Predominant models for predicting rates of sediment transport face acute shortcomings when applied to coastal boundary layers. This is due to a neglect of the web of stochastic variables governing the rate of sediment dislodgement. While stochastic models do exist, the parametric extent of their validity tends to be limited,...
Wave energy has the potential to power large and small factions of economies around the world alike. Current methods for determining the amount of wave energy resource available to wave energy converter (WEC) devices entail capturing the look of the sea state at large by presenting characteristic wave heights, periods,...
Ocean Wave Energy Converters (WECs) operating on the water surface are subject to storms and other extreme events. In particular, high and steep waves, especially breaking waves, are likely the most dangerous to WECs. A method for quantifying the breaking severity of waves is presented and applied to wave data...
In coastal and ocean engineering, understanding the ocean environment and the forces from waves, tsunamis and waterborne debris on structures and floating bodies is an important aspect of designing safe and effective infrastructure. Understanding the impact of these forces on structures becomes an important question in the design process. Answering...
As coastal communities face increasing chronic and acute hazards, nature-based coastal engineering solutions have experienced a rapid growth in popularity and interest. Recent works on this topic have shown that “Green Infrastructure” may be effective at mitigating coastal hazards and therefore provide sustainable adaptation alternatives to traditional engineering solutions such...
Due to global warming wildland fires are increasing in frequency and severity. In the case of wildland fires, the major modes of combustion occur include smoldering combustion and flaming combustion. Smoldering combustion occurs most commonly in porous fuels like peat, forest duff, and woody fuels, which are available in abundance...
This Thesis aims to determine whether we can improve the accuracy, resolution, and speed of calculations for common power system problems using simple computational models that scale well to machine learning and high performance computing solutions. The second chapter of this Thesis implements more precise aging and degradation models for...
This project was carried out collaboratively by Oregon State University (OSU) and the Oregon Department of Geology and Mineral Industries (DOGAMI) and involved baseline observations and
modeling at the proposed wave energy conversion (WEC) array site near Reedsport, OR. In particular, observations and predictions of the wave conditions at the...
Full Text:
-Haller, J.C. Allan, J.A. Barth, M.C. Haller,
R.A. Holman, and P. Ruggiero
This project was
This project was carried out collaboratively by Oregon State University (OSU) and the Oregon Department of Geology and Mineral Industries (DOGAMI) and involved baseline observations and
modeling at the proposed wave energy conversion (WEC) array site near Reedsport, OR. In particular, observations and predictions of the wave conditions at the...
Full Text:
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18
Appendix C: Optical Remote Sensing Results
By Rob Holman, Oregon State University
This project was carried out collaboratively by Oregon State University (OSU) and the Oregon Department of Geology and Mineral Industries (DOGAMI) and involved baseline observations and
modeling at the proposed wave energy conversion (WEC) array site near Reedsport, OR. In particular, observations and predictions of the wave conditions at the...
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 rip current circulation cells exist with alongshore spacing of O(1OOm) even though the nearshore bathymetry displayed...
This thesis contains a manuscript describing the implementation of a high resolution wave forecasting model for the coasts of Washington and Oregon. The purpose of this project was to advance the wave predictive capabilities of the states of Oregon and the southwest part of Washington by including the effects of...
The U.S. Pacific Northwest is home to one of the most extreme wave climates in the world with waves of 10 m in height arriving to the coast approximately each year. With an average water temperature of 12℃, the beaches in the region are too cold to go on a...
Turbulent flows over rough surfaces are encountered in many engineering and geophysical applications. Flows of this nature, due to their increasing technological interests, have been a subject of rigorous investigation in recent years. Of the particular interest to the oceanographic community is the study of turbulent oscillatory flow over rough...
Laboratory data of free surface elevations and fluid velocities were
obtained using a laser-Doppler velocimeter for the case of a periodic wave
plunging over an impermeable, steep (1:10) slope with a fixed bottom roughness.
The measurements were conducted over 15 cross-shore locations from the outer
surf zone to the swash...
VCO-based ADCs have recently emerged as attractive alternative to conventional DeltaSigma (ΔΣ) modulator architectures. Few salient features of a VCObased ADC are: 1) the quantization noise is 1st order noise shaped, 2) it is an open loop architecture, and, 3) its implementation is mostly digital in nature. Hence, they are...
This dissertation examines properties and representations of several isotropic Gaussian random fields in the unit ball in d-dimensional Euclidean space. First we consider Lévy's Brownian motion. We use an integral representation for the covariance function to find a new expansion for Lévy's Brownian motion as an infinite linear combination of...
Despite numerous techniques for measuring and estimating water depth, bathymetry in the nearshore zone is notoriously difficult to map. Dangerous sea states, noisy environmental conditions, and expensive survey operations, particularly in remote areas, contribute to the difficulties of obtaining data along the coast. Global datasets, derived mainly from satellite altimetry...
Theories predict that making a dilute magnetic semiconductor strongly p -type would allow it to remain ferromagnetic at room temperature. This is of intrest as a ferromagnetic semiconductor would allow for a great many applications in the field of spintronics. Neutron scattering experiments were undertaken to better understand the antiferromagnetic...
In this dissertation we study the electromagnetic properties of planar waveguides
with non-magnetic strongly anisotropic dielectric cores. We develop an analytical
description of the mode propagation in these systems and show that the index
of refraction can be either positive or negative depending on the specific material
parameters. Propagating modes...
This work addresses the application of Nonlinear Model Predictive Control (NMPC) to a class of ocean wave energy conversion systems in which the cost functional is not in a standard quadratic form, and the WEC model includes the nonlinear effects, such as the hydrodynamic viscous drag. The NMPC implementation is...
This thesis addresses Micro Aerial Vehicle (MAV) control by leveraging learning based techniques to improve robustness of the control system. Applying classical control methods to MAVs is a difficult process due to the complexity of the control laws with fast and highly non-linear dynamics. These methods are mostly based on...
The use of autonomous robots in complex exploration tasks is rapidly increasing. Indeed, robots can provide speed and cost effectiveness in many tasks, as well as allow operation in environments that are hostile to humans. In this dissertation we: 1) provide two adaptive navigation algorithms; 2) develop a coordination mechanism;...
As the functionality of digital chips continues to increase dramatically, chip- to-chip communication bandwidths must scale accordingly to avoid constraining the overall system performance. Therefore, high speed transceiver design has be- come an important research topic. In particular, the performance of the circuits that are responsible for timing accuracy are...
For years, the Oregon fishing industry has argued that the lack of coastal cold storage designed to handle seafood has severely limited the opportunity to develop value-added products and retain seafood industry employment. Once landed, the majority of Oregon seafood spends little time on the coast, and a large portion...
Tree-like patterns are ubiquitous in nature. Botanical trees, river networks, and blood systems are the most well-known examples of complex hierarchical systems met in observations. Interestingly, many of such systems exhibit statistical self-similarity. There are two main types of self-similarity: Horton self-similarity and Tokunaga self-similarity. Although there is an increased...
Reflection of an obliquely incident solitary wave at a vertical wall is studied experimentally in the laboratory wave tank. Precision measurements of water-surface variations are achieved with the aid of laser-induced fluorescent (LIF) technique and detailed temporal and spatial features of the
Mach reflection are captured. During the development stage...
We examine the interactions and feedbacks between bathymetry, waves, currents, and
sediment transport. The first two pro jects focus on the use of remote sensing techniques
to expand our knowledge of the nearshore. Due to the plethora of snap-shot data that is
available from satellites and their distribution via Google...
Velocity measurements from drifter GPS records are assimilated and used in an ensemble-based inversion 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, USA. The Regional Ocean Modeling System (ROMS) is used to...
Following the installation of a street car
system, or for that matter, any other electric system,
using the ground return, or the rail return which comes
in contact with the ground, there is always more or
less trouble experienced by water or gas companies,
using metal pipe, due to the...
Continual growth of the world's energy consumption and the demand for long-term clean renewable energy resources has led to the development of ocean-based wave energy technologies. Emerging technologies are advancing potential solutions to the complex problem of energy generation in the harsh and corrosive ocean environment. To develop these technologies,...
Purposes and Method of Study
The purpose of this study was to find out if tenth grade girls
were aware of the probability that a majority of them would work at
some time during their lives, and if they planned to prepare for this
possibility. A questionnaire was designed and...
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...
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...
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...
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...
As the second largest river in the U.S., the entrance to the Columbia River is home to some of the most extreme wave conditions on the Pacific Coast. Winter storms commonly generate waves 6-8 m in height, which in combination with strong tidal currents, can produce dangerous navigation conditions. To...
Wave runup is an important physical process that affects nearshore sediment transport, coastal erosion, and flooding. Large and unexpected runup events can also be dangerous to beach goers. Extreme runup statistics are essential parameters used in engineering design of marine structures and in coastal management. Although the study of runup...
In this study, 3D finite difference and 2D finite element forward modeling were used to create an electromagnetic sensitivity analysis for the Cotopaxi volcano in Ecuador. Magnetotellurics (MT) is a natural-source electromagnetic geophysical technique that images electrical conductivity. Measuring strong contrasts in electrical conductivity in volcanic materials allows for the...
The surf zone exhibits large energetic signals from wave shoaling and subsequent dissipation due to breaking, forcing circulation. The bathymetry responds to the wave and wave-induced circulation with the growth, transport, and destruction of large scale bathymetric features, such as mega ripples and sand bars. There is an obvious fluctuation...
Surf zone eddies (f < 0.01 Hz) are important in nearshore mixing, shoreline erosion, the distribution of pollutants, and ecological processes, such as offshore transport of larvae. Surf zone eddies have traditionally been treated as two-dimensional features with horizontal length scales larger than the local water depth. Studies by Lippmann...
