Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 12 of 12
Full-Text Articles in Engineering
The Tides They Are A-Changin’: A Comprehensive Review Of Past And Future Nonastronomical Changes In Tides, Their Driving Mechanisms And Future Implications, Ivan D. Haigh, Mark D. Pickering, J.A. Mattias Green, Brian K. Arbic, Arne Arns, Soenke Dangendorf, David Hill, David A. Jay, Multiple Additional Authors
The Tides They Are A-Changin’: A Comprehensive Review Of Past And Future Nonastronomical Changes In Tides, Their Driving Mechanisms And Future Implications, Ivan D. Haigh, Mark D. Pickering, J.A. Mattias Green, Brian K. Arbic, Arne Arns, Soenke Dangendorf, David Hill, David A. Jay, Multiple Additional Authors
Civil and Environmental Engineering Faculty Publications and Presentations
Scientists and engineers have observed for some time that tidal amplitudes at many locations are shifting considerably due to non-astronomical factors. Here we review comprehensively these important changes in tidal properties, many of which remain poorly understood. Over long geological time-scales, tectonic processes drive variations in basin size, depth, and shape, and hence the resonant properties of ocean basins. On shorter geological time-scales, changes in oceanic tidal properties are dominated by variations in water depth. A growing number of studies have identified widespread, sometimes regionally-coherent, positive and negative trends in tidal constituents and levels during the 19th, 20th and early …
Internal Gravity Waves And Meso/Submesoscale Currents In The Ocean Anticipating High-Resolution Observations From The Swot Swath Altimeter Mission, Edward D. Zaron, Cesar B. Rocha
Internal Gravity Waves And Meso/Submesoscale Currents In The Ocean Anticipating High-Resolution Observations From The Swot Swath Altimeter Mission, Edward D. Zaron, Cesar B. Rocha
Civil and Environmental Engineering Faculty Publications and Presentations
The article offers information on the meeting “Interactions between Internal Gravity Waves and Meso/Submesoscale Currents in the Ocean," held in Portland, Oregon, on February 10-11, 2018. Topics discussed include the role played by geostationary satellites in atmospheric science, the result of interactions between high-frequency internal gravity waves and low-frequency mesoscale andsubmesoscale currents in the ocean, and kinetic energy spectrum of surface currents.
Multimodal Internal Waves Generated Over A Subcritical Ridge: Impact Of The Upper-Ocean Stratification, Xie Jieshuo, Jiayi Pan, David A. Jay
Multimodal Internal Waves Generated Over A Subcritical Ridge: Impact Of The Upper-Ocean Stratification, Xie Jieshuo, Jiayi Pan, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
Interaction of barotropic tides with subsurface topography is vital to ocean mixing. Yet the behavior of large-amplitude, nonlinear, internal solitary waves (ISWs) that can cause strong mixing remains poorly understood, especially that of higher-mode and multimodal internal waves. Therefore, a 2.5-dimensional, nonhydrostatic model with adjustable vertical resolution was developed to investigate effects of upper-ocean stratification on tidally induced multimodal internal waves and to show how they are generated by the subcritical ridge where only upward-propagating internal wave beams (IWBs) are present. The effects of the stratification on properties and characteristics of the excited IWBs and on the energy partition of …
Tides And The Swot Mission: Transition From Science Definition Team To Science Team, Brian K. Arbic, Florent Lyard, Aurelien Ponte, Richard D. Ray, James G. Richman, Jay F. Shriver, Edward Zaron, Zhongxiang Zhao
Tides And The Swot Mission: Transition From Science Definition Team To Science Team, Brian K. Arbic, Florent Lyard, Aurelien Ponte, Richard D. Ray, James G. Richman, Jay F. Shriver, Edward Zaron, Zhongxiang Zhao
Civil and Environmental Engineering Faculty Publications and Presentations
As the SWOT wide-swath satellite altimeter mission transitions from the Science Definition Team to the Science Team, it is an opportune time to review the progress that has been made with respect to tides, and the work remaining to be done. As with previous altimeter missions, tides present both an opportunity and a challenge for the SWOT mission. The TOPEX/Jason class of altimeters have allowed high-accuracy mapping of open-ocean barotropic tides over their coverage latitudes (66°S to 66°N), but the inter-track spacing of these missions (~150 km) has limited their ability to map smaller-scale features such as shelf tides, coastal …
Non-Stationary Internal Tides Observed With Satellite Altimetry, Richard D. Ray, Edward D. Zaron
Non-Stationary Internal Tides Observed With Satellite Altimetry, Richard D. Ray, Edward D. Zaron
Civil and Environmental Engineering Faculty Publications and Presentations
Temporal variability of the internal tide is inferred from a 17-year combined record of Topex/Poseidon and Jason satellite altimeters. A global sampling of along-track sea-surface height wavenumber spectra finds that non-stationary variance is generally 25% or less of the average variance at wavenumbers characteristic of mode-1 tidal internal waves. With some exceptions the non-stationary variance does not exceed 0.25 cm2. The mode-2 signal, where detectable, contains a larger fraction of non-stationary variance, typically 50% or more. Temporal subsetting of the data reveals interannual variability barely significant compared with tidal estimation error from 3-year records. Comparison of summer vs. winter conditions …
The Surface Expression Of Semidiurnal Internal Tides Near A Strong Source At Hawaii. Part I: Observations And Numerical Predictions, Cedric Chavanne, P. Flament, Glenn S. Carter, M. Merrifield, D. Luther, Edward D. Zaron, K. W. Gurgel
The Surface Expression Of Semidiurnal Internal Tides Near A Strong Source At Hawaii. Part I: Observations And Numerical Predictions, Cedric Chavanne, P. Flament, Glenn S. Carter, M. Merrifield, D. Luther, Edward D. Zaron, K. W. Gurgel
Civil and Environmental Engineering Faculty Publications and Presentations
Observations of semidiurnal currents fromhigh-frequency radioDoppler currentmeters andmoored acoustic Doppler current profilers (ADCPs) in the Kauai Channel, Hawaii, are described and compared with two primitive equation numerical models of the tides. The Kauai Channel, separating the islands of Oahu and Kauai, is a site of strong internal tide generation by the barotropic tides flowing over Kaena Ridge, the subsurface extension of Oahu. The nature and impacts of internal tide generation in the Kauai Channel were intensively studied during the 2002–03 near-field component of the Hawaii Ocean Mixing Experiment. Comparisons of observed coherent (i.e., phase locked to the astronomical forcing)M2 …
Initial Expansion Of The Columbia River Tidal Plume: Theory And Remote Sensing Observations, David A. Jay, Edward D. Zaron, Jiayi Pan
Initial Expansion Of The Columbia River Tidal Plume: Theory And Remote Sensing Observations, David A. Jay, Edward D. Zaron, Jiayi Pan
Civil and Environmental Engineering Faculty Publications and Presentations
Analysis of the Columbia River tidal plume using Lagrangian frontal equations provides a concise description of the evolution of frontal depth H, velocity U, reduced gravity g', and frontal internal Froude number F (sub R) . Because the estuary mouth is narrow, the initial radial plume motion is supercritical (F (sub R) > 1) for up to 12 hours. Understanding this supercritical phase is vital, because plume properties change rapidly, with strong ecosystem impacts. To analyze this expansion, analytical and numerical models (the latter with three mixing formulations) were tested. Model results are compared to synthetic aperture radar images to verify …
Determining Azimuthal Variations In Frontal Froude Number From Sar Imagery, Jiayi Pan, David A. Jay, Hui Lin
Determining Azimuthal Variations In Frontal Froude Number From Sar Imagery, Jiayi Pan, David A. Jay, Hui Lin
Civil and Environmental Engineering Faculty Publications and Presentations
River plume fronts are the locus of strong mixing between plume and ambient coastal waters, contribute to coastal productivity, and exert a major impact on coastal ecosystems. The frontal Froude number Fr is an important parameter characterizing the frontal status with respect to both propagation and vertical mixing. In this study, we examine azimuthal variations in Fr using a new remote sensing method. We derive Fr from SAR image data on the basis of the SAR imaging theory and the mechanism of internal wave fission at front. This method is applied to a SAR image showing a front off the …
Effects Of Ambient Velocity Shear On Nonlinear Internal Wave Associated Mixing At The Columbia River Plume Front, Jiayi Pan, David A. Jay
Effects Of Ambient Velocity Shear On Nonlinear Internal Wave Associated Mixing At The Columbia River Plume Front, Jiayi Pan, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
Large-amplitude nonlinear internal waves (NLIWs) are frequently observed propagating away from Columbia River tidal plume fronts. They are generated because of the deceleration of the frontal bulge. During the River Influences on Shelf Ecosystems project cruises, the velocity, density structure and acoustic backscatter of the plume fronts and frontal NLIWs were observed using a towed vehicle, vessel-mounted instrumentation, and a vessel X band radar. These observations indicate that in the presence of strong ambient velocity shear, the NLIWs with maximum amplitudes occur well below the density interface and at a depth deeper than in the absence of shear. This deepening …
Frontal Processes In The Columbia River Plume Area, David A. Jay, Jiayi Pan, Philip M. Orton, Alexander R. Horner-Devine
Frontal Processes In The Columbia River Plume Area, David A. Jay, Jiayi Pan, Philip M. Orton, Alexander R. Horner-Devine
Civil and Environmental Engineering Faculty Publications and Presentations
Information about frontal processes in the Columbia River plume area. Topics include: phenomenology of CR plume fronts, plume responses, upwelling fronts & internal waves: the "Zipper", etc.
Residual Circulation In Shallow Estuaries 1. Highly Stratified, Narrow Estuaries, David A. Jay, J. Dungan Smith
Residual Circulation In Shallow Estuaries 1. Highly Stratified, Narrow Estuaries, David A. Jay, J. Dungan Smith
Civil and Environmental Engineering Faculty Publications and Presentations
Long-wave theory and simple turbulence closures have been used to show that three distinct types of circulation (highly stratified, weakly stratified, and partially mixed) arise in narrow, shallow estuaries from the finite amplitude of the tide and the interaction of stratification with vertical mixing. Each type has a different dominant process causing the vertical exchange of salt and fresh water on the flood, and each gives rise to a characteristic residual circulation. The tidal circulation in highly stratified shallow estuaries, described herein, is the result of a finite amplitude internal motion driven by the barotropic tide; shear instabilities at the …
Residual Circulation In Shallow Estuaries 2. Weakly Stratified And Partially Mixed, Narrow Estuaries, David A. Jay, J. Dungan Smith
Residual Circulation In Shallow Estuaries 2. Weakly Stratified And Partially Mixed, Narrow Estuaries, David A. Jay, J. Dungan Smith
Civil and Environmental Engineering Faculty Publications and Presentations
Long-wave theory is used herein to analyze circulation in weakly stratified and partially mixed estuaries. Unlike the highly stratified systems considered in part 1, the flows considered here have only a minimal tidal-frequency internal wave component. These estuaries may therefore be modeled as the sum of weakly interacting barotropic and baroclinic modes. The dominant factors driving the residual flow are finite amplitude barotropic effects in weakly stratified estuaries and a combination of barotropic effects and steady horizontal density gradient forcing in partially mixed estuaries. The dominant vertical exchange mechanism in the weakly stratified case is bottom boundary-induced turbulence, and that …