Index Catalog // ScholarsArchive@OSU

Numerical experiments on the effects of a meridional ridge on the transmission of energy by barotropic Rossby waves

Creator:: Matano, Ricardo P.
Abstract:: Analytical and numerical models are used to study the effects of a meridional ridge on the propagation of barotropic Rossby waves produced by distant wind stress forcing. The analytical model illustrates the qualitative aspects of the problem by solving a simplified form of the potential vorticity equation. The analytical results...
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Chlorophyll enchancement and mixing associated with meanders of the shelf break front in the Mid-Atlantic Bight

Creator:: Ryan, J. P., Yoder, J. A., Barth, John A., and Cornillon, P. C.
Abstract:: Meanders of the shelf break front in the Mid-Atlantic Bight (MAB) during April and May of 1997 were associated with chlorophyll enhancement along a hydrographic and a topographic feature. The hydrographic feature was the surface outcrop of the front, which ranged from ~10 to >100 km seaward of the shelf...
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Location and dynamics of the Antarctic Polar Front from satellite sea surface temperature data

Creator:: Moore, J. Keith, Abbott, Mark R., and Richman, James G.
Abstract:: The location of the Antarctic Polar Front (PF) was mapped over a 7-year period (1987-1993) within images of satellite-deprived sea surface temperature. The mean path of the PF is strongly steered by the topographic features of the Southern Ocean. The topography places vorticity constraints on the dynamics of the PF...
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Time Evolution of Surface Chlorophyll Patterns From Cross-Spectrum Analysis of Satellite Color Images

Creator:: Denman, Kenneth L. and Abbott, Mark R.
Abstract:: Sequences of coastal zone color scanner (CZCS) images from the offshore region adjacent to Vancouver Island, Canada, have been analyzed to estimate the time rate of decorrelation of surface phytoplankton chlorophyll pigment patterns. In these high-latitude, high-pigment areas, CZCS-derived pigment estimates were lower than those obtained from ship samples by...
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Observations of Phytoplankton and Nutrients from a Lagrangian Drifter off Northern California

Creator:: Abbott, Mark R., Brink, Kenneth H., Booth, D. R., Blasco, Dolors, Codispoti, L. A., Niiler, Pearn P., and Ramp, Steven R.
Abstract:: A Lagrangian drifter was deployed in a cold filament off northern California as part of the Coastal Transition Zone program. The drifter was equipped with an optical package (consisting of a spectroradiometer, a fluorometer, and a beam transmissometer) suspended at 8.5-m depth and a water sampler suspended at 16.3-m depth....
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Satellite-based detection and monitoring of phytoplankton blooms along the Oregon coast

Creator:: McKibben, S. M., Strutton, P. G., Foley, D. G., Peterson, T. D., and White, A. E.
Abstract:: We have applied a normalized difference algorithm to 8 day composite chlorophyll-a (CHL) and fluorescence line height (FLH) imagery obtained from the Moderate Resolution Imaging Spectroradiometer aboard the Aqua spacecraft in order to detect and monitor phytoplankton blooms in the Oregon coastal region. The resulting bloom products, termed CHL[subscript rel]...
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An interlaboratory comparison of techniques for extracting and analyzing trapped gases in ice cores

Creator:: Sowers, Todd, Brook, Edward J., Etheridge, David, Blunier, Thomas, Fuchs, Andreas, Leuenberger, Markus, Chappellaz, Jerome, Barnola, Jean Marc, Wahlen, Martin, Deck, Bruce, and Weyhenmeyer, Connie
Abstract:: We undertook an interlaboratory comparison of techniques used to extract and analyze trapped gases in ice cores. The intercomparison included analyses of standard reference gases and samples of ice from the Greenland Ice Sheet Project 2 (GISP2) site. Concentrations of CO₂, CH₄, the δ¹⁸O of O₂, the δ¹⁵N of N₂,...
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The spring transition in currents over the Oregon continental shelf

Creator:: Huyer, Adrianna, 1945-, Sobey, E. J. C., and Smith, Robert L. (Robert Lloyd), 1935-
Abstract:: Current meter moorings maintained over the Oregon continental shelf in 1973 and 1975 clearly show the difference between winter and spring oceanographic regimes and the rapid transition between the regimes. In winter the mean alongshore current is northward at all depths and strongest near shore; there is no mean vertical...
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Horizontal transport and the distribution of nutrients in the coastal transition zone off Northern California: effects on primary production, phytoplankton biomass and species composition

Creator:: Chavez, Francisco P., Barber, Richard T., Kosro, P. Michael, 1951-, Huyer, Adriana, 1945-, Ramp, Steven R., Stanton, Timothy P., and Rojas de Mendiola, Blanca
Abstract:: Conductivity‐temperature‐depth surveys during 1988 encountered strong baroclinic jets that were evident in acoustic Doppler current profiler and hydrographic data. During June and July 1988 a filament with high surface nitrate, high chlorophyll, abundant populations of neritic centric diatoms, and higher rates of primary production was evident perpendicular to the coast...
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Estimation of surface winds from upward looking acoustic doppler current profilers

Creator:: Brown, J., Barton, E.D., Trasvina, A., Velez, H.S., Kosro, P. Michael, 1951-, and Smith, Robert L. (Robert Lloyd), 1935-
Abstract:: Three upward looking acoustic Doppler current profilers (ADCP) were deployed beneath meteorological buoys in the Gulf of Tehuantepec, Mexico, during winter 1988-1989. Hourly averaged wind speed data from the buoys and from ship when in the vicinity were compared with surface acoustic backscatter intensity recorded at the ADCPs. The backscatter...
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Structure of the coastal current field off Northern California during the coastal ocean dynamics experiment

Creator:: Kosro, P. Michael, 1951-
Abstract:: For 74 days during the spring and summer upwelling seasons of 1981 and 1982, in conjunction with the Coastal Ocean Dynamics Experiment, profiles of upper ocean currents were collected in the waters over the shelf and slope off northern California using a shipboard Doppler acoustic log. These measurements provide detailed...
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Offshore wind forcing in the Gulf of Tehuantepec, Mexico: the asymmetric circulation

Creator:: Trasviña, A., Barton, E.D., Brown, J., Velez, H.S., Kosro, P. Michael, 1951-, and Smith, Robert L. (Robert Lloyd), 1935-
Abstract:: Since the early surveys carried out by the Eastern Tropical Pacific (EASTROPIC) and Scripps Tuna Oceanographic Research (STOR) projects in the tropical Pacific off Mexico, the northerly winds which blow over the Gulf of Tehuantepec were described as an Important factor controlling the dynamics of this coastal ocean. In January-February...
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Sea surface drag coefficients in the Risø Air Sea Experiment

Creator:: Mahrt, Larry, Vickers, Dean, Howell, Jim, Hojstrup, Jorgen, Wilczak, James M., Edson, Jim, and Hare, Jeffrey
Abstract:: This study examines the dependence of the computed drag coefficient on wind speed, stability, fetch, flux sampling problems, and method of calculation of the drag coefficient. The analysis is applied to data collected at a tower 2 km off the coast of Denmark during the Risø Air Sea Experiment (RASEX)....
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The Batchelor spectrum and dissipation in the upper ocean

Creator:: Dillon, Thomas M. and Caldwell, Douglas R.
Abstract:: Observations of vertical temperature microstructure at ocean station P during the mixed layer experiment (Mile) indicate that the shape of the high-frequency temperature gradient spectrum depends on the relative strengths of turbulence and stratification. For low Cox number ((dT/dz)²)/ (dT/dz)²• the linear range of the Batchelor spectrum is not well...
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A new method for estimating the turbulent heat flux at the bottom of the daily mixed layer

Creator:: Imawaki, Shiro, Niiler, Pearn P., Gautier, Catherine H., Halpern, David, Knox, Robert A., Large, William G., Luther, Douglas S., McWilliams, James C., Moum, James N., and Paulson, Clayton A.
Abstract:: A new method is presented for estimating the vertical turbulent heat flux at the bottom of the daily mixed layer from the temperature data in the mixed layer and net solar irradiance data at the sea surface. We assume that fluctuations in the divergence of advective heat flux have longer...
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Energy-containing scales of turbulence in the ocean thermocline

Creator:: Moum, James N.
Abstract:: From measurements of the energy‐containing scales of turbulence in the ocean thermocline, two new formulations are examined: (1) an inviscid estimate for the viscous dissipation rate of turbulent kinetic energy and (2) a mixing length estimate for the turbulent heat flux. These formulations are tested using coincident measurements of the...
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An optimized design for a moored instrument array in the tropical Atlantic Ocean

Creator:: Hackert, Eric C., Miller, Robert N., and Busalacchi, Antonio J.
Abstract:: This paper presents a series of observing system simulation experiments (OSSEs) which are intended as a design study for a proposed array of instrumented moorings in the tropical Atlantic Ocean. Fields of TOPEX/Poseidon sea surface height anomalies are subsampled with the goal being reconstruction of the original fields through the...
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Semidiurnal internal tide in JASIN: Observations and simulation

Creator:: deWitt, L. M., Levine, Murray D., Paulson, C. A., and Burt, W. V.
Abstract:: Temperature was observed in the upper 80 m by moored thermistor chains at three locations in Rockall Channel west of Scotland. Isotherms were interpolated, and a 1‐week period of exceptionally energetic tidal oscillations was analyzed. The moored array (horizontal separations ranging from 6 to 20 km) was used as an...
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Extracting the internal tide from data: Methods and observations from the Mixed Layer Dynamics Experiment

Creator:: Levine, Murray D. and Richman, James G.
Abstract:: Several methods are developed for analyzing data containing a highly variable internal tide. In particular, the methods are aimed at the analysis of moored observations with relatively few measurements in the vertical. The analysis depends upon an "elliptical decomposition" that is a generalization of the familiar "rotary decomposition." The technique...
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The upper ocean internal wave field: Influence of the surface and mixed layer

Creator:: Levine, Murray D.
Abstract:: A model is developed to calculate the upper ocean internal wave spectrum as modified by the surface boundary and mixed layer. The Garrett‐Munk spectrum is assumed to describe the deep ocean wave field. The main effect of the surface and mixed layer is to align the vertical structure of the...
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Internal waves under the Arctic pack ice during the Arctic Internal Wave Experiment: The coherence structure

Creator:: Levine, Murray D.
Abstract:: The spectral composition of internal gravity waves under the Arctic pack ice during the Arctic Internal Wave Experiment (AIWEX) was found to be strikingly different from observations at lower latitudes. Time series of vertical displacement were inferred from horizontal and vertical arrays of temperature and conductivity sensors. Frequency spectra indicate...
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Internal wave dissipation under sea ice

Creator:: Morison, James H., Long, Charles E., and Levine, Murray D.
Abstract:: The dissipation of internal wave energy in the turbulent boundary layer under pack ice is determined using a time‐varying boundary layer model with an eddy coefficient closure scheme. The magnitude of the eddy coefficient is determined by the ice drift velocity, which is assumed greater than the rms water velocity...
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Dynamics of mean and subtidal flow on the New England shelf

Creator:: Shearman, R. Kipp and Lentz, Steven J.
Abstract:: Current and hydrographic observations from the Coastal Mixing and Optics experiment moored array, deployed from August 1996 through June 1997, are used to describe the velocity variability and evaluate the dynamics of circulation over the New England shelf on timescales ranging from a few days to several months. Subtidal (days...
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Observations of near-inertial waves in acoustic doppler current profiler measurements made during the mixed layer dynamics experiment

Creator:: Chereskin, T. K., Levine, Murray D., Harding, A. J., and Regier, L. A.
Abstract:: Measurements of upper ocean shear made during the Mixed Layer Dynamics Experiment (MILDEX) provide evidence of large horizontal scale motion at near‐inertial frequency. The measurements consist of shipboard acoustic Doppler current profiles. Four large‐scale spatial surveys of 2–4 days duration were made by the R/V Wecoma as a set of...
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Boussinesq modeling of a rip current system

Creator:: Chen, Qin, Dalrymple, Robert A., Kirby, James T., Kennedy, Andrew B., and Haller, Merrick C.
Abstract:: 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,...
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The variation in the inherent optical properties of phytoplankton near an absorption peak as determined by various models of cell structure

Creator:: Zaneveld, J. Ronald and Kitchen, James C.
Abstract:: Optical oceanography models of attenuation and scattering properties often contain simple spectral relationships. Electromagnetic theory, however, predicts fluctuations in the spectra of the attenuation coefficients and scattering properties of substances at wavelengths near an absorption peak. We have modeled these effects for phytoplankton using homogeneous, two‐layered, and three‐layered sphere models...
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Error in predicting hydrosol backscattering from remotely sensed reflectance

Creator:: Weidemann, A. D., Stavn, R. H., Zaneveld, J. Ronald, and Wilcox, M. R.
Abstract:: Monte Carlo simulations are carried out to determine the error in the inversion of backscattering from remotely sensed reflectance when geometrical shape factors of the light field are assumed to be unity. The results show that error in backscattering inversion can vary from a 40% overestimation to a 20% underestimation...
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Temporal variations of beam attenuation coefficient on the Continental Rise off Nova Scotia

Creator:: Pak, Hasong and Zaneveld, J. Ronald
Abstract:: Two separate time series observations of light transmission in the bottom water on the Continental Rise off Nova Scotia show fluctuations of light transmission in a wide range, 0-50% transmission at λ = 660 nm. The range corresponds approximately to SPM concentrations of 12 mg/l to 150 μg/l. The former...
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On the noncorrelation of the vertical structure of light scattering and chlorophyll α in case I waters

Creator:: Kitchen, James C. and Zaneveld, J. Ronald
Abstract:: The relationships between beam attenuation, absorption, suspended particle concentration, size distribution and pigment content are examined for a region where the particle concentration and pigment maxima are widely separated. Mie scattering analyses are performed on this data to predict the profiles of backscattering. It was found that absorption and scattering...
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Infragravity waves over a natural barred profile

Creator:: Sallenger, Asbury H., Jr. and Holman, Robert A.
Abstract:: Measurements of cross-shore flow were made across the surf zone during a storm as a nearshore bar became better developed and migrated offshore. Measured infragravity band spectra were compared to synthetic spectra calculated numerically over the natural barred profile assuming a white run-up spectrum of leaky mode or high-mode edge...
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Atmospheric conditions during the spring and fall transitions in the coastal ocean off western United States

Creator:: Strub, P. Ted and James, Corinne
Abstract:: We examine large-scale atmospheric behavior around the time of the spring and fall transitions in the coastal ocean off the west coast of North America. Records of adjusted sea level (ASL), coastal wind stress, sea level atmospheric pressure (SLP), and 500-mbar heights for the years 1971-1975 and 1980-1983 are analyzed....
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Wave variance partitioning in the trough of a barred beach

Creator:: Howd, Peter A., Oltman-Shay, Joan, and Holman, Robert A.
Abstract:: The wave-induced velocity field in the nearshore is composed of contributions from incident wind waves (f > 0.05 Hz), surface infragravity waves (f < 0.05 Hz, lkl < (σ²/gβ) and shear waves (f < 0.05 Hz, lkl > σ²/gβ), where ƒ is the frequency, σ = 2πf, k is the...
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Edge waves in the presence of strong longshore currents

Creator:: Howd, Peter A., Bowen, Anthony J., and Holman, Robert A.
Abstract:: A form of the linear, inviscid shallow water wave equation which includes alongshore uniform, but cross-shore variable, longshore currents and bathymetry is presented. This formulation provides a continuum between gravity waves (either leaky or edge waves) on a longshore current, and the recently discovered shear waves. In this paper we...
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Shear instabilities of the mean longshore current : 1. theory

Creator:: Bowen, A. J. and Holman, Robert A.
Abstract:: A new class of nearshore waves based on the shear instability of a steady longshore current is discussed. The dynamics depend on the conservation of potential vorticity but with the background vorticity field, traditionally the role of Coriolis in larger scale flows, supplied by the shear structure of the longshore...
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Large-scale sea surface temperature variability from satellite and shipboard measurements

Creator:: Berstein, R. L. and Chelton, Dudley B.
Abstract:: A series of satellite sea surface temperature (SST) intercomparison workshops were conducted under NASA sponsorship at the Jet Propulsion Laboratory. Three different satellite data sets were compared with each other, with routinely collected ship data, and with climatology for the months of November 1979, December 1981, March 1982, and July...
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Characterizing the circulation off the Kenyan-Tanzanian coast using an ocean model

Creator:: Mayorga-Adame, C. Gabriela, Strub, P. Ted, Batchelder, Harold P., and Spitz, Yvette H.
Abstract:: The Kenyan-Tanzanian coastal region in the western Indian Ocean faces several environmental challenges including coral reef conservation, fisheries management, coastal erosion, and nearshore pollution. The region lacks hydrodynamic records and oceanographic studies at adequate spatial and temporal scales to provide information relevant to the local environmental issues. We have developed...
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Forcing and variability of nonstationary rip currents

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...
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Modeled ocean circulation in Nares Strait and its dependence on landfast-ice cover

Creator:: Shroyer, Emily L., Samelson, Roger M., Padman, Laurie, and Münchow, Andreas
Abstract:: Two simplified ocean simulations are used to study circulation and transport within Nares Strait. The simulations are similar, except that one included a coupled sea ice model that effectively established a landfast ice cover throughout the simulation year. Comparison between the ocean-only and ocean-ice simulations reveals a systematic change in...
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On the dynamics of the Zanzibar Channel

Creator:: Zavala-Garay, J., Theiss, J., Moulton, M., Walsh, C., van Woesik, R., Mayorga-Adame, C. G., García‐Reyes, M., Mukaka, D. S., Whilden, K., and Shaghude, Y. W.
Abstract:: The Zanzibar Channel lies between the mainland of Tanzania and Zanzibar Island in the tropical western Indian Ocean, is about 100 km long, 40 km wide, and 40 m deep, and is essential to local socioeconomic activities. This paper presents a model of the seasonal and tidal dynamics of the...
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Simulation of the melt season using a resolved sea ice model with snow cover and melt ponds

Creator:: Skyllingstad, Eric D., Shell, Karen M., Collins, Lee, and Polashenski, Chris
Abstract:: A three-dimensional sea ice model is presented with resolved snow thickness variations and melt ponds. The model calculates heating from solar radiative transfer and simulates the formation and movement of brine/melt water through the ice system. Initialization for the model is based on observations of snow topography made during the...
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Altimeter-derived seasonal circulation on the southwest Atlantic shelf: 27°–43°S

Creator:: Strub, P. Ted, James, Corinne, Combes, Vincent, Matano, Ricardo P., Piola, Alberto R., Palma, Elbio D., Saraceno, Martin, Guerrero, Raul A., Fenco, Harold, and Ruiz-Etcheverry, Laura A.
Abstract:: Altimeter sea surface height (SSH) fields are analyzed to define and discuss the seasonal circulation over the wide continental shelf in the SW Atlantic Ocean (27°–43°S) during 2001–2012. Seasonal variability is low south of the Rio de la Plata (RdlP), where winds and currents remain equatorward for most of the...
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Shoreline variability from days to decades : results of long-term video imaging

Creator:: Pianca, C., Holman, R., and Siegle, E.
Abstract:: The present work characterizes the time-space scales of variability and forcing dependencies of a unique 26 year record of daily to hourly shoreline data from a steep beach at Duck, North Carolina. Shoreline positions over a 1500 m alongshore span were estimated using a new algorithm called ASLIM based on...
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Spatial and temporal variability of freshwater discharge into the Gulf of Alaska

Creator:: Hill, D. F., Bruhis, N., Calos, S. E., Arendt, A., and Beamer, J.
Abstract:: A study of the freshwater discharge into the Gulf of Alaska (GOA) has been carried out. Using available streamgage data, regression equations were developed for monthly flows. These equations express discharge as a function of basin physical characteristics such as area, mean elevation, and land cover, and of basin meteorological...
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Climate change impacts on wave and surge processes in a Pacific Northwest (USA) estuary

Creator:: Cheng, T. K., Hill, D. F., Beamer, J., and García-Medina, G.
Abstract:: Total water levels (TWLs) within estuaries are influenced by tides, wind, offshore waves, and streamflow, all of which are uniquely affected by climate change. The magnitude of TWL associated with various return periods is relevant to understanding how the hydrodynamics of a bay or estuary may evolve under distinct climate...
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Energy and heat fluxes due to vertically propagating Yanai waves observed in the equatorial Indian Ocean

Creator:: Smyth, W. D., Durland, T. S., and Moum, J. N.
Abstract:: Shipboard current measurements in the equatorial Indian Ocean in October and November of 2011 revealed oscillations in the meridional velocity with amplitude ~0.10 m/s. These were clearest in a layer extending from ~300 to 600 m depth and had periods near 3 weeks. Phase propagation was upward. Measurements from two...
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Integrated modeling framework to quantify the coastal protection services supplied by vegetation

Creator:: Guannel, Greg, Ruggiero, Peter, Faries, Joe, Arkema, Katie, Pinsky, Malin, Gelfenbaum, Guy, Guerry, Anne, and Kim, Choong-Ki
Abstract:: Vegetation can protect communities by reducing nearshore wave height and altering sediment transport processes. However, quantitative approaches for evaluating the coastal protection services, or benefits, supplied by vegetation to people in a wide range of coastal environments are lacking. To begin to fill this knowledge gap, we propose an integrated...
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Regional variations in the influence of mesoscale eddies on near-surface chlorophyll

Creator:: Gaube, Peter, McGillicuddy, Dennis J., Jr., Chelton, Dudley B., Behrenfeld, Michael J., and Strutton, Peter G.
Abstract:: Eddies can influence biogeochemical cycles through a variety of mechanisms, including the excitation of vertical velocities and the horizontal advection of nutrients and ecosystems, both around the eddy periphery by rotational currents and by the trapping of fluid and subsequent transport by the eddy. In this study, we present an...
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Evaluation of directly wind-coherent near-inertial surface currents off Oregon using a statistical parameterization and analytical and numerical models

Creator:: Kim, Sung Yong, Kosro, P. Michael, and Kurapov, Alexander L.
Abstract:: Directly wind-coherent near-inertial surface currents off the Oregon coast are investigated with a statistical parameterization of observations and outputs of a regional numerical ocean model and three one-dimensional analytical models including the slab layer, Ekman, and near-surface averaged Ekman models. The transfer functions and response functions, statistically estimated from observed...
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Simulating extreme total water levels using a time-dependent, extreme value approach

Creator:: Serafin, Katherine A. and Ruggiero, Peter
Abstract:: Coastal flood hazard zones and the design of coastal defenses are often devised using the maximum recorded water level or a ‘‘design’’ event such as the 100 year return level, usually projected from observed extremes. Despite technological advances driving more consistent instrumental records of waves and water levels, the observational...
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Microwave backscattering from surf zone waves

Creator:: Catalán, Patricio A., Haller, Merrick C., and Plant, William J.
Abstract:: 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,...
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Surf zone bathymetry and circulation predictions via data assimilation of remote sensing observations

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...
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The dynamics of pressure and form drag on a sloping headland: Internal waves versus eddies

Creator:: Warner, Sally J. and MacCready, Parker
Abstract:: Topographically generated eddies and internal waves have traditionally been studied separately even though bathymetry that creates both phenomena is abundant in coastal regions. Here a numerical model is used to understand the dynamics of eddy and wave generation as tidal currents flow past Three Tree Point, a 1 km long,...
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Application of the implicit particle filter to a model of nearshore circulation

Creator:: Miller, R. N. and Ehret, L. L.
Abstract:: The implicit particle filter is applied to a stochastically forced shallow water model of nearshore flow, and found to produce reliable state estimates with tens of particles. The state vector of this model consists of a height anomaly and two horizontal velocity components at each point on a 128 x...
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A two-way nested simulation of the oceanic circulation in the Southwestern Atlantic

Creator:: Combes, Vincent and Matano, Ricardo P.
Abstract:: This article presents the results of a high-resolution (1/12°), two-way nested simulation of the oceanic circulation in the southwestern Atlantic region. A comparison between the model results and extant observations indicates that the nested model has skill in reproducing the best-known aspects of the regional circulation, e.g., the volume transport...
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Intrathermocline eddies in the coastal transition zone off central Chile (31–41°S)

Creator:: Hormazabal, Samuel, Combes, Vincent, Morales, Carmen E., Correa-Ramirez, Marco A., Di Lorenzo, Emmanuel, and Nuñez, Sergio
Abstract:: The three-dimensional structure and the origin of mesoscale anticyclonic intrathermocline eddies (ITEs) in the coastal transition zone (CTZ) off central Chile (31–41°S) were analyzed through the combination of data from oceanographic cruises and satellite altimetry, and the application of an eddy-resolving primitive equation ocean model coupled with a numerical experiment...
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Satellite observations of chlorophyll, phytoplankton biomass, and Ekman pumping in nonlinear mesoscale eddies

Creator:: Gaube, P., Chelton, D. B., Strutton, P. G., and Behrenfeld, Michael J.
Abstract:: Nonlinear mesoscale eddies can influence biogeochemical cycles in the upper ocean through vertical and horizontal advection of nutrients and marine organisms. The relative importance of these two processes depends on the polarity of an eddy (cyclones versus anticyclones) and the initial biological conditions of the fluid trapped in the core...
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Poleward propagating subinertial alongshore surface currents off the U.S. West Coast

Creator:: Kim, Sung Yong, Cornuelle, Bruce D., Terrill, Eric J., Jones, Burt, Washburn, Libe, Moline, Mark A., Paduan, Jeffrey D., Garfield, Newell, Largier, John L., Crawford, Greg, and Kosro, P. Michael
Abstract:: The network comprising 61 high-frequency radar systems along the U.S. West Coast (USWC) provides a unique, high resolution, and broad scale view of ocean surface circulation. Subinertial alongshore surface currents show poleward propagating signals with phase speeds of O(10) and O(100–300) km d⁻¹ that are consistent with historical in situ...
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A comparison of mechanisms generating vertical transport in the Brazilian coastal upwelling regions

Creator:: Mazzini, P. L. F. and Barth, John A.
Abstract:: Several mechanisms can drive vertical velocities in the coastal ocean, including wind-forcing and through gradients in the vorticity field generated by flow-topography interactions. A two-layer, steady, wind-driven, analytical model is applied to the major upwelling systems of Brazil : Cabo Frio (CF) and Cabo de Santa Marta (CSM) regions. Comparisons...
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Effects of the diurnal cycle in solar radiation on the tropical Indian Ocean mixed layer variability during wintertime Madden-Julian Oscillations

Creator:: Li, Yuanlong, Han, Weiqing, Shinoda, Toshiaki, Wang, Chunzai, Lien, Ren-Chieh, Moum, James N., and Wang, Jih-Wang
Abstract:: The effects of solar radiation diurnal cycle on intraseasonal mixed layer variability in the tropical Indian Ocean during boreal wintertime Madden-Julian Oscillation (MJO) events are examined using the HYbrid Coordinate Ocean Model. Two parallel experiments, the main run and the experimental run, are performed for the period of 2005–2011 with...
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Estimating the Bowen ratio over the open and ice-covered ocean

Creator:: Andreas, Edgar L., Jordan, Rachel E., Mahrt, Larry, and Vickers, Dean
Abstract:: The Bowen ratio, the ratio of the turbulent surface fluxes of sensible (Hₛ) and latent (Hₗ) heat, Bo ≡ Hₛ/Hₗ, occurs throughout micrometeorology. It finds application in the Bowen ratio and energy budget method, where it provides both turbulent heat fluxes when only the available energy at the surface is...
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Distribution and sources of organic matter in surface marine sediments across the North American Arctic margin

Creator:: Goni, Miguel A., O’Connor, Alison E., Kuzyk, Zou Zou, Yunker, Mark B., Gobeil, Charles, and Macdonald, Robie W.
Abstract:: As part of the International Polar Year research program, we conducted a survey of surface marine sediments from box cores along a section extending from the Bering Sea to Davis Strait via the Canadian Archipelago. We used bulk elemental and isotopic compositions, together with biomarkers and principal components analysis, to...
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Modulation of the sea-surface temperature in the Southeast Pacific by the atmospheric low-level coastal jet

Creator:: Hong, Xiaodong, Wang, Shouping, Holt, Teddy R., Martin, Paul J., and O’Neill, Larry
Abstract:: The atmospheric low-level coastal jet (LLCJ) in the Southeast Pacific (SEP) region is characterized as either a strong-forcing jet (colder and drier air) or weak-forcing jet (warm and moist) based on the location of the Southeast Pacific high-pressure system (SEPH). The sea-surface temperature (SST) changes corresponding to a particularly strong-forcing...
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Bathymetry correction using an adjoint component of a coupled nearshore wave-circulation model: Tests with synthetic velocity data

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...
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Observations of near-inertial surface currents off Oregon: Decorrelation time and length scales

Creator:: Kim, Sung Yong and Kosro, P. Michael
Abstract:: High-resolution (km in space and hourly in time) surface currents observed by an array of high-frequency radars off Oregon are analyzed to quantify the decorrelation time and length scales of their near-inertial motions. The near-inertial surface currents are dominantly clockwise with amplitudes of 9-12 cm s⁻¹. However, they appear asymmetric...
Resource Type:: Article

Quantifying the length-scale dependence of surf zone advection

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

cBathy: A robust algorithm for estimating nearshore bathymetry

Creator:: Holman, Rob, Plant, Nathaniel, and Holland, Todd
Abstract:: A three-part algorithm is described and tested to provide robust bathymetry maps based solely on long time series observations of surface wave motions. The first phase consists of frequency-dependent characterization of the wave field in which dominant frequencies are estimated by Fourier transform while corresponding wave numbers are derived from...
Resource Type:: Article

Temporal variability of near-bottom dissolved oxygen during upwelling off central Oregon

Creator:: Adams, Katherine A., Barth, John A., and Chan, Francis
Abstract:: In the productive central-Oregon coastal upwelling environment, wind-driven upwelling, tides, and topographic effects vary across the shelf, setting the stage for varied biogeochemical responses to physical drivers. Current, temperature, salinity, and dissolved oxygen (DO) measurements from three moorings deployed during the upwelling seasons of 2009–2011 off the central-Oregon coast are...
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Biological production in the NE Pacific and its influence on air-sea CO2 flux: Evidence from dissolved oxygen isotopes and O2/Ar

Creator:: Juranek, L. W., Quay, P. D., Feely, R. A., Lockwood, D., Karl, D. M., and Church, M. J.
Abstract:: We determine rates of gross photosynthetic O₂ production (GOP) and net community O₂ production (NCP) using the triple oxygen isotope and O₂/Ar approach on two spring and two late summer meridional transects of the NE Pacific. Observed GOP and NCP in the subtropical (89 ± 9 and 8.3 ± 1.3...
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Near-inertial motions off the Oregon Coast

Creator:: Anderson, Lain, Huyer, Adriana, 1945-, and Smith, Robert L. (Robert Lloyd), 1935-
Abstract:: Near‐inertial motions were observed at all current meters in an array of five moorings spanning the continental margin off central Oregon during October 1977 to January 1978. All moorings were between 10 and 130 km from shore, in water depths between 100 m and 2500 m. Largest near‐inertial amplitudes (>30...
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Evaluation of the air-sea bulk formula and sea-surface temperature variability from observations

Creator:: Vickers, Dean and Mahrt, Larry
Abstract:: Eddy‐correlation fluxes are compared to air‐sea fluxes predicted by a widely used bulk flux formulation without wave‐state effects. Systematic discrepancies are found. For example, the model approximately equates the roughness lengths for heat and moisture; however, the observed roughness length for heat (zoh) exceeds that for moisture (zoq) by an...
Resource Type:: Article

Surface patterns in temperature, flow, phytoplankton biomass, and species composition in the coastal transition zone of northern California

Creator:: Hood, Raleigh R., Abbott, Mark R., Huyer, Adriana, 1945-, and Kosro, P. Michael, 1951-
Abstract:: Satellite thermal imagery and in situ biological and physical data are presented that describe the spatial variability of phytoplankton biomass and species composition in relation to the physical structure at the sea surface during persistent upwelling off northern California. Surface patterns in temperature, geostrophic velocity, chlorophyll, and particle size structure...
Resource Type:: Article

Phytoplankton pigment patterns and wind forcing off central California

Creator:: Abbott, Mark R. and Barksdale, Brett
Abstract:: We use a 4-year time series of high-resolution coastal zone color scanner imagery to study mesoscale variability in phytoplankton pigment (as a surrogate for biomass) distributions off central California during the spring–summer upwelling season. We use empirical orthogonal functions to decompose the time series of spatial images into its dominant...
Resource Type:: Article

Phytoplankton and photosynthetic light response in the coastal transition zone off northern California in June 1987

Creator:: Hood, Raleigh R., Abbott, Mark R., and Huyer, Adriana, 1945-
Abstract:: In June 1987 the geostropic flow in the coastal transition zone off northern California (between 50 and 150 km off the coast from Point Reyes to just north of Cape Mendocino) was dominated by a well-defined, southward-meandering current. Three vertical sections are presented that show the hydrographic structure of the...
Resource Type:: Article

Tidal and atmospheric forcing of the upper ocean in the Gulf of California: Part 1. Sea surface temperature variability

Creator:: Paden, Cynthia A., Abbott, Mark R., and Winant, C. D.
Abstract:: Two years of satellite infrared imagery (1984–1986) are used to examine the sea surface temperature (SST) variability in the northern Gulf of California. Empirical orthogonal functions (EOFs) of the temporal and spatial SST variance for 20 monthly mean images show that the dominant SST patterns are generated by spatially varying...
Resource Type:: Article

Statistical properties of near surface currents in the California coastal transition zone

Creator:: Brink, K. H., Beardsley, R. C., Niiler, Pearn P., Abbott, Mark R., Huyer, Adriana, 1945-, Ramp, S., Stanton, T., and Stuart, D.
Abstract:: During the summers of 1987 and 1988, 77 near-surface satellite-tracked drifters were deployed in or near cold filaments near Point Arena, California (39ºN), and tracked for up to 6 months as part of the Coastal Transition Zone (CTZ) program. The drifters had large drogues centered at 15 m, and the...
Resource Type:: Article

The structure of the transition zone between coastal waters and the open ocean off northern California, winter and spring 1987

Creator:: Kosro, P. Michael, 1951-, Huyer, Adriana, 1945-, Ramp, S. R., Smith, Robert L. (Robert Lloyd), 1935-, Chavez, F. P., Cowles, Timothy J., Abbott, Mark R., Strub, P. Ted, Barber, R. T., Jessen, P., and Small, Lawrence F.
Abstract:: Physical and biological fields in the coastal transition zone off northern California were measured during February, March, May and June 1987 in an extended alongshore region between 60 km and 150 km offshore. The spring transition, as seen in coastal sea level and winds, occurred in mid-March. Surface variability during...
Resource Type:: Article

Estimate of bottom and surface stress during a spring-neap tide cycle by dynamical assimilation of tide gauge observations in the Chesapeake Bay

Creator:: Spitz, Yvette and Klinck, J. M.
Abstract:: Dynamical assimilation of surface elevation from tide gauges is investigated to estimate the bottom drag coefficient and surface stress as a first step in improving modeled tidal and wind-driven circulation in the Chesapeake Bay. A two-dimensional shallow water model and an adjoint variational method with a limited memory quasi-Newton optimization...
Resource Type:: Article

Estimation of Time Averages from Irregularly Spaced Observations: With Application to Coastal Zone Color Scanner Estimates of Chlorophyll Concentration

Creator:: Chelton, Dudley B. and Schlax, Michael C.
Abstract:: A formalism is presented for quantifying the sampling error of an arbitrary linear estimate of a time-averaged quantity constructed from a time series of irregularly spaced observations at a fixed location. The method is applicable to any irregularly sampled time series; it is applied here to satellite observations of chlorophyll...
Resource Type:: Article

The sea state bias in altimeter estimates of sea level from collinear analysis of TOPEX data

Creator:: Chelton, Dudley B.
Abstract:: The wind speed and significant wave height (H1/3) dependencies of the sea state is in altimeter estimates of sea level, expressed in the form ∆hSSB=bH1/3, are examined from least squares analysis of 21 cycles of collinear TOPEX data. The bias coefficient b is found to increase in magnitude with increasing...
Resource Type:: Article

Variability in satellite winds over the Benguela upwelling system during 1999–2000

Creator:: Risien, Craig M., Reason, C. J. C., Shillington, F. A., and Chelton, Dudley B.
Abstract:: Wind stress variability over the Benguela upwelling system is considered using 16 months (01 August 1999 to 29 November 2000) of satellite-derived QuikSCAT wind data. Variability is investigated using a type of artificial neural network, the self-organizing map (SOM), and a wavelet analysis. The SOM and wavelet analysis are applied...
Resource Type:: Article

Correction to "Aliased tidal errors in TOPEX/POSEIDON sea surface height data”

Creator:: Schlax, Michael G. and Chelton, Dudley B.
Resource Type:: Article

Aliased tidal errors in TOPEX/POSEIDON sea surface height data

Creator:: Schlax, Michael G. and Chelton, Dudley B.
Abstract:: Alias periods and wavelengths for the M2, S2, N2, K1, O1, and P1 tidal constituents are calculated for TOPEX/POSEIDON. Alias wavelengths calculated in previous studies are shown to be in error, and a correct method is presented. With the exception of the K1 constituent, all of these tidal aliases for...
Resource Type:: Article

Detecting aliased tidal errors in altimeter height measurements

Creator:: Schlax, Michael G. and Chelton, Dudley B.
Abstract:: A simple statistic is derived for quantifying the potential for the aliasing of tidal errors in a given linear estimate of sea surface height constructed from altimeter data. The existence of M2 tidal constituent errors in Geosat data processed in the traditional way (i.e., with orbit errors removed using least...
Resource Type:: Article

Effects of a Coastal Front on the Distribution of Chlorophyll in Lake Tahoe, California-Nevada

Creator:: Leigh-Abbott, Mark R., Coil, John A., Powell, Thomas M., and Richerson, Peter J.
Abstract:: The existence of a distinct coastal zone is confirmed in Lake Tahoe (California-Nevada) by horizontal transects measuring chlorophyll and temperature simultaneously. Creation of the coastal region is influenced by bottom topography, the nature of the surface wind stress, and the difference between physical processes occurring within a Rossby radius of...
Resource Type:: Article

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