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Diffusively-Driven Overturning Of A Stable Density Gradient, Andrew F. Thompson, George Veronis Jan 2005

Diffusively-Driven Overturning Of A Stable Density Gradient, Andrew F. Thompson, George Veronis

Journal of Marine Research

We present the results of an experimental study on the formation and propagation of thermohaline intrusions from an initial state that is stably stratified in two diffusing components. The intrusions form in a layer that contains compensating horizontal gradients of the two components and that lies above a denser reservoir layer that is homogeneous. In the initial state, a vertical barrier separates the upper layer into two half layers each with a different concentration but with the same density. Differential diffusion of solute from the reservoir into the upper layer initiates intrusions that are separated by an interface and that …

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Preformed Phosphate, Soft Tissue Pump And Atmospheric Co2, Takamitsu Ito, Michael J. Follows Jan 2005

Preformed Phosphate, Soft Tissue Pump And Atmospheric Co2, Takamitsu Ito, Michael J. Follows

Journal of Marine Research

We develop a new theory relating atmospheric pCO2 and the efficiency of the soft tissue pump of CO2 in the ocean, measured by P*, a quasi-conservative tracer. P* is inversely correlated with preformed phosphate, and its global average represents the fraction of nutrients transported by the export and remineralization of organic material. This view is combined with global conservation constraints for carbon and nutrients leading to a theoretical prediction for the sensitivity of atmospheric pCO2 to changes in globally averaged P*. The theory is supported by sensitivity studies with a more complex, …

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Homoclinic Bifurcations In The Quasi-Geostrophic Double-Gyre Circulation, Eric Simonnet, Michael Ghil, Henk Dijkstra Jan 2005

Homoclinic Bifurcations In The Quasi-Geostrophic Double-Gyre Circulation, Eric Simonnet, Michael Ghil, Henk Dijkstra

Journal of Marine Research

The wind-driven double-gyre circulation in a rectangular basin goes through several dynamical regimes as the amount of lateral friction is decreased. This paper studies the transition to irregular flow in the double-gyre circulation by applying dynamical systems methodology to a quasi-geostrophic, equivalent-barotropic model with a 10-km resolution.The origin of the irregularities, in space and time, is the occurrence of homoclinic bifurcations that involve phase-space behavior far from stationary solutions. The connection between these homoclinic bifurcations and earlier transitions, which occur at larger lateral friction, is explained. The earlier transitions, such as pitchfork and asymmetric Hopf bifurcation, only involve the nonlinear …

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The Variability Of The East Sakhalin Current Induced By Winds Over The Continental Shelf And Slope, Genta Mizuta, Kay I. Ohshima, Yasushi Fukamachi, Masaaki Wakatsuchi Jan 2005

The Variability Of The East Sakhalin Current Induced By Winds Over The Continental Shelf And Slope, Genta Mizuta, Kay I. Ohshima, Yasushi Fukamachi, Masaaki Wakatsuchi

Journal of Marine Research

Long-term current measurements of the East Sakhalin Current (ESC) in the Sea of Okhotsk are analyzed using the technique of empirical orthogonal functions (EOFs) in the frequency domain. The first and second EOFs at subtidal frequencies represent motions over the continental shelf and slope, respectively, corresponding to the variability of the two cores of the intense ESC. The first EOF can be explained by the first-mode coastal trapped wave (CTW). The structure of the second EOF is similar to that of the second-mode CTW to the first approximation. According to the distribution of the cross-spectra between EOFs and the wind …

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Effects Of Habitat Complexity And Hydrodynamics On The Abundance And Diversity Of Small Invertebrates Colonizing Artificial Substrates, Nazan Atilla, John W. Fleeger, Christopher M. Finelli Jan 2005

Effects Of Habitat Complexity And Hydrodynamics On The Abundance And Diversity Of Small Invertebrates Colonizing Artificial Substrates, Nazan Atilla, John W. Fleeger, Christopher M. Finelli

Journal of Marine Research

Invertebrate colonization in a shallow estuarine embayment was studied with the use of artificial substrates (bottle brushes) to create and mimic complex habitats. Substrates were manipulated to obtain varying levels of habitat density and surface area by shortening and/or removing bristles from the brushes. Complexity was quantified as the total surface area of bristles and bristle surface area within the geometric volume of the substrate (i.e., bristle density). Short-bristled brushes provided greater habitat density while long-bristled brushes provided larger surface area within the same removal treatment. Abundance of invertebrates that recruited from the water column (mostly from the meiobenthos) averaged …

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Intense Short-Period Internal Waves In The Ocean, Konstantin Sabinin, Andrey Serebryany Jan 2005

Intense Short-Period Internal Waves In The Ocean, Konstantin Sabinin, Andrey Serebryany

Journal of Marine Research

Trains of quasi-periodic high-frequency internal waves (IWs) of large amplitude are common in the upper thermocline of the ocean. Sources for these waves may be different ones but it is not always possible to experimentally establish them for certain. We analyzed results of many IW experiments carried out in different representative regions of the World Ocean, including continental margins in the Mid-Atlantic Bight, in the northwestern Pacific at Kamchatka, the Seyshelles-Mascarene bottom rise, and some regions of the open ocean where the intense short-period IWs occur. Comparative analysis of the intense IWs observed in the Mid-Atlantic Bight and at Kamchatka …

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Speculations On A Schematic Theory Of The Younger Dryas, Carl Wunsch Jan 2005

Speculations On A Schematic Theory Of The Younger Dryas, Carl Wunsch

Journal of Marine Research

The possible implications of a change in deep ocean mixing generated by the abrupt coverage of continental shelves during deglaciation is explored schematically. A simple Cartesian continental shelf/deep ocean tidal model is used to mimic the behavior of tidal dissipation at a variety of frequencies relative to a basin-near-resonance. The actual estimated sea level curve is then used to calculate a representative deep water tidal dissipation through time, which is then translated by means of a one-dimensional loop flow to explore the implications of a change in deep ocean mixing. It is possible to pick parameters for the loop model, …

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Nonlinear Double-Diffusive Intrusions At The Equator, Neil R. Edwards, Kelvin J. Richards Jan 2004

Nonlinear Double-Diffusive Intrusions At The Equator, Neil R. Edwards, Kelvin J. Richards

Journal of Marine Research

Previous, linear analysis has suggested that observations of interleaving, quasi-horizontal layers in the equatorial oceans may be explained by double-diffusive or inertial instability. Here we describe an idealized, two-dimensional, numerical investigation of the nonlinear development of these instabilities, focusing almost exclusively on the double-diffusive case. We consider the mechanisms for equilibration and maintenance of the interleaving intrusions and perform a thorough sensitivity analysis. Nonlinearity arising from changes in diffusive regime is found to be more important than advective nonlinearity in promoting global equilibration. When variations in effective flux ratio are weak, local constraints prevent equilibration until large amplitudes are reached. …

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Respiration And Vertical Carbon Flux In The Gulf Of Maine Water Column, T. T. Packard, J. P. Christensen Jan 2004

Respiration And Vertical Carbon Flux In The Gulf Of Maine Water Column, T. T. Packard, J. P. Christensen

Journal of Marine Research

The transport of carbon from ocean surface waters to the deep sea is a critical factor in calculations of planetary carbon cycling and climate change. This vertical carbon flux can be calculated by integrating the vertical profile of the seawater respiration rate but is rarely done because measuring seawater respiration is so difficult. However, seawater respiratory oxygen consumption is the product of the combined activity of all the respiratory electron transfer systems in a seawater community of bacterioplankton, phytoplankton, and zooplankton. This respiratory electron transfer system (ETS) is the membrane bound enzymatic system that controls oxygen consumption and ATP production …

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Rapid Physical And Biological Particle Mixing On An Intertidal Sandflat, Anthony F. D'Andrea, Glenn R. Lopez, Robert C. Aller Jan 2004

Rapid Physical And Biological Particle Mixing On An Intertidal Sandflat, Anthony F. D'Andrea, Glenn R. Lopez, Robert C. Aller

Journal of Marine Research

Sediment mixing processes were investigated using inert tracer experiments, benthic macrofaunal community analysis, and surveys of ray feeding pits to quantify the relative rates and controls of physical and biological reworking on Debidue Flat, an intertidal sandflat in South Carolina. Sediment reworking on Debidue Flat was rapid, with both advective and biodiffusive mixing operating over different vertical spatial scales. Physical reworking by tidal currents dominated initial transport of the tracer in the top 5-10 cm on timescales of ~30 days. Although the exact mechanism of tracer transport is unclear, it is most likely due to active fluidization of surface sediments …

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Influence Of Short-Term Variations In Food On Survival Of Crassostrea Gigas Larvae: A Modeling Study, Eric N. Powell, Eleanor A. Bochenek, John M. Klinck, Eileen E. Hofmann Jan 2004

Influence Of Short-Term Variations In Food On Survival Of Crassostrea Gigas Larvae: A Modeling Study, Eric N. Powell, Eleanor A. Bochenek, John M. Klinck, Eileen E. Hofmann

Journal of Marine Research

A biochemically-based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster, Crassostrea gigas. The model defines larvae in terms of their protein, lipid, carbohydrate, and ash content and includes variation in growth efficiency and egg quality to better simulate cohort population dynamics. Changes in tissue composition occur as the larva grows and in response to the biochemical composition of the food. The premise behind this modeling study was that certain periods of larval life are more critical than others with respect to the availability of food and that food quality is as …

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Adhesive-Based Selection By A Tentacle-Feeding Polychaete For Particle Size, Shape And Bacterial Coating In Silt And Sand, Ruben A. Guieb, Peter A. Jumars, Robert F. L. Self Jan 2004

Adhesive-Based Selection By A Tentacle-Feeding Polychaete For Particle Size, Shape And Bacterial Coating In Silt And Sand, Ruben A. Guieb, Peter A. Jumars, Robert F. L. Self

Journal of Marine Research

We tested particle selection by a surface deposit-feeding, tentaculate spionid polychaete, Pseudopolydora kempi japonica Imajima and Hartman. In experiments with peroxide-cleaned, sizegraded but otherwise natural silts and sands, individual worms showed peak preference for particles 80-99 μm in diameter, compared with previous (Self and Jumars, 1988) documentation of peak preference for particles of 7 μm in experiments conducted with plastic and glass beads. These results imply that microtektites will not in general be good tracers of mixing of mineral grains of comparable size. Animals exhibited statistically significant but not marked differences in size selectivity for subrounded versus subangular grain shapes; …

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Representativeness Of Meridional Hydrographic Sections In The Western South Atlantic, A. M. Thurnherr, K. G. Speer Jan 2004

Representativeness Of Meridional Hydrographic Sections In The Western South Atlantic, A. M. Thurnherr, K. G. Speer

Journal of Marine Research

Many studies of the oceanic circulation are based on data collected during quasi-synoptic hydrographic surveys. After spatial averaging, to filter out the effects of mesoscale variability, it is often explicitly or implicitly assumed that the synoptic hydrographic gradients are representative of a quasi-steady "mean" state. Climatological tracer fields and float data at the depth of the North Atlantic Deep Water in the western South Atlantic (Brazil Basin) support the notion of a quasi-steady mean circulation characterized by alternating bands of primarily zonal flow with meridional scales of several hundreds of km. Visually, the mean circulation appears to dominate three samples …

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Winter Conditions In The Irminger Sea Observed With Profiling Floats, L. R. Centurioni, W. J. Gould Jan 2004

Winter Conditions In The Irminger Sea Observed With Profiling Floats, L. R. Centurioni, W. J. Gould

Journal of Marine Research

Temperature/salinity profiles collected between 1994 and 2003 with profiling floats in the North Atlantic subpolar gyre are analyzed to investigate the hydrographic conditions in winter in the Irminger Sea. The salinity data can be calibrated against accurate profiles from ships obtained mostly during summer months and the resulting float profile salinity accuracy is of the order of 0.015. Between 1997 and 2003, when the North Atlantic Oscillation (NAO) index was generally low, the potential temperature and salinity of the Labrador Sea Water (LSW) core observed by the floats showed a positive trend, an indication of little or no deep convection. …

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Monitoring The Meridional Overturning Circulation In The North Atlantic: A Model-Based Array Design Study, Johanna Baehr, Jöel Hirschi, Jens-Olaf Beismann, Jochem Marotzke Jan 2004

Monitoring The Meridional Overturning Circulation In The North Atlantic: A Model-Based Array Design Study, Johanna Baehr, Jöel Hirschi, Jens-Olaf Beismann, Jochem Marotzke

Journal of Marine Research

A monitoring system for the meridional overturning circulation (MOC) is deployed into an "eddy-permitting" numerical model (FLAME) at three different latitudes in the North Atlantic Ocean. The MOC is estimated by adding contributions related to Ekman transports to those associated with the zonally integrated vertical velocity shear. Ekman transports are inferred from surface wind stress, whereas the velocity shear is derived from continuous density "observations," principally near the eastern and western boundaries, employing thermal wind balance. The objective is to test the method and array setups for possible real observation in the ocean at the chosen latitudes and to guide …

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The Effect Of Topography On The Steady-State Wind And Buoyancy-Driven Subtropical Gyre, L. A. Walkington, A. J. Willmott Jan 2004

The Effect Of Topography On The Steady-State Wind And Buoyancy-Driven Subtropical Gyre, L. A. Walkington, A. J. Willmott

Journal of Marine Research

This paper studies the impact of topography and increased vertical resolution on steady-state wind and buoyancy-driven circulation in the Subtropical Gyre. Buoyancy driving is represented by mass exchange across the interface separating layers of constant density. The mass exchange in turn is parameterized in terms of the departure of a layer thickness from a reference value. A 2-layer ocean model is developed that incorporates topography that depends on the meridional co-ordinate, and the problem reduces to solving a first order partial differential equation governing the upper layer inverse planetary potential vorticity. Two distinct families of characteristic curves are required to …

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Observations And Modeling Of Seasonal Variability In The Straits Of Georgia And Juan De Fuca, Diane Masson, Patrick F. Cummins Jan 2004

Observations And Modeling Of Seasonal Variability In The Straits Of Georgia And Juan De Fuca, Diane Masson, Patrick F. Cummins

Journal of Marine Research

The Strait of Georgia is a large semi-enclosed basin on the southern coast of British Columbia. Its main connection to the Pacific is to the south, through Juan de Fuca Strait. Abundant freshwater discharge, mainly from the Fraser River, forces an estuarine exchange with oceanic shelf water. The resulting circulation is modulated by tides and winds. Both the coastal wind stress and the flux of freshwater are subject to strong seasonal modulations, producing a marked seasonal cycle in the water properties and circulation of the region. The seasonal variability of the Strait of Georgia and Juan de Fuca Strait is …

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Potential Vorticity Dynamics In A Domain With Closed Geostrophic Contours. I: Steady Linear Flows, Andrew E. Kiss Jan 2004

Potential Vorticity Dynamics In A Domain With Closed Geostrophic Contours. I: Steady Linear Flows, Andrew E. Kiss

Journal of Marine Research

Inertia-less wind-driven barotropic flow with lateral and Ekman friction is investigated in circular basins with various bathymetries. The focus is on the vorticity dynamics of flow in basins encircled by continental shelves, a bathymetry which allows a recirculating flow at lowest order because the geostrophic contours are distorted into closed loops which do not intersect the boundary. In general the wind forcing and friction will not balance everywhere, and the potential vorticity lost to the wind must be recovered elsewhere on each streamline. This recovery takes place in a "western" boundary current if geostrophic contours intersect the boundary, but the …

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Physical Forcing Of Phytoplankton Community Structure And Primary Production In Continental Shelf Waters Of The Western Antarctic Peninsula, B. B. Prézelin, E. E. Hofmann, M. Moline, J. M. Klinck Jan 2004

Physical Forcing Of Phytoplankton Community Structure And Primary Production In Continental Shelf Waters Of The Western Antarctic Peninsula, B. B. Prézelin, E. E. Hofmann, M. Moline, J. M. Klinck

Journal of Marine Research

Analyses of a multidisciplinary data set, collected in continental shelf waters of the Western Antarctic Peninsula (WAP) during austral summer of January 1993, identified a previously unrecognized forcing mechanism that sets up a physical and chemical structure that supports and assures site-specific diatom-dominated communities and enhanced biological production (Prézelin et al., 2000). This forcing is active when the southern boundary of the Antarctic Circumpolar Current (ACC) flows along the shelf edge, thereby facilitating onshelf bottom intrusions of nutrient-rich Upper Circumpolar Deep Water (UCDW), which then is upwelled or mixed into the upper water column. At times or locations where UCDW …

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Variability Of The Biological Front South Of Africa From Seawifs And A Coupled Physical-Biological Model, J. Llido, E. Machu, J. Sudre, I. Dadou, V. Garçon Jan 2004

Variability Of The Biological Front South Of Africa From Seawifs And A Coupled Physical-Biological Model, J. Llido, E. Machu, J. Sudre, I. Dadou, V. Garçon

Journal of Marine Research

The spatio-temporal variability of the biological front in the Agulhas Current system is investigated by comparing SeaWiFS chlorophyll a data and modeled chlorophyll fields over the October 1997–October 2001 period. The latter fields are simulated using a regional eddy-permitting (1/3° × 1/3°) coupled physical (AGAPE)-biological model forced by the monthly atmospheric NCEP/NCAR reanalysis. The annual cycle of the observed chlorophyll within the Agulhas Current system biogeochemical provinces is quite well reproduced by the model. The modeled phase of the seasonality in the SWSIG (South Western Subtropical Indian Gyre) is opposite to that of the SCZ (Subtropical Convergence Zone encompassing the …

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Oxygen Variability In The Near-Surface Waters Of The Northern North Atlantic: Observations And A Model, Peter Lazarevich, Tom Rossby, Craig Mcneil Jan 2004

Oxygen Variability In The Near-Surface Waters Of The Northern North Atlantic: Observations And A Model, Peter Lazarevich, Tom Rossby, Craig Mcneil

Journal of Marine Research

As part of the World Ocean Circulation Experiment a major study was undertaken to determine the absolute circulation of the Subpolar North Atlantic using a large number of acoustically tracked isopycnal floats deployed on the 27.5 σ surface. Fifty floats were equipped with sensors to study dissolved oxygen from a Lagrangian perspective. In this paper we comment on very large variations in oxygen along trajectories of fluid parcels that outcrop in winter and resubduct the following spring. We employ a one-dimensional model to interpret these in terms of biophysical processes at and near the surface. In an attempt to …

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Linear Instabilities Of A Two-Layer Geostrophic Surface Front Near A Wall, Angelique C. Haza, Nathan Paldor, Arthur J. Mariano Jan 2004

Linear Instabilities Of A Two-Layer Geostrophic Surface Front Near A Wall, Angelique C. Haza, Nathan Paldor, Arthur J. Mariano

Journal of Marine Research

The development of linear instabilities on a geostrophic surface front in a two-layer primitive equation model on an ƒ-plane is studied analytically and numerically using a highly accurate differential shooting method. The basic state is composed of an upper layer in which the mean flow has a constant potential vorticity, and a quiescent lower layer that outcrops between a vertical wall and the surface front (defined as the line of intersection between the interface that separates the two layers and the ocean's surface). The characteristics of the linear instabilities found in the present work confirm earlier results regarding the …

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Observations Of Wind Influence On Exchange Flows In A Strait Of The Chilean Inland Sea, Arnoldo Valle-Levinson, José Luis Blanco Jan 2004

Observations Of Wind Influence On Exchange Flows In A Strait Of The Chilean Inland Sea, Arnoldo Valle-Levinson, José Luis Blanco

Journal of Marine Research

A > 100-day time series of velocity profiles, sea level and wind velocity at a strait in the Chilean Inland Sea was analyzed to examine the effects of wind forcing on the mean two-layer exchange. Measurements took place in the Meninea Constriction of the Moraleda Channel during a period dominated by northerly winds. The mean flow in the strait, and in general in the Moraleda Channel, showed net surface northward outflow and net bottom southward inflow that likely resulted from the dynamical balance between pressure gradient and friction. The influence of tidal mixing on mean exchange flows was further suggested by …

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Conceptual Models Of Early Diagenetic Processes: The Muddy Seafloor As An Unsteady, Batch Reactor, Robert C. Aller Jan 2004

Conceptual Models Of Early Diagenetic Processes: The Muddy Seafloor As An Unsteady, Batch Reactor, Robert C. Aller

Journal of Marine Research

Conceptual models of early diagenetic processes in sedimentary deposits guide interpretation and investigation of compositional patterns, elemental fluxes, and biogeochemical interactions. The ideas that sediments are open to exchange, are laterally homogeneous, and often accrete steadily upward underlie most diagenetic theory. Net accumulation rate of a deposit is thus a master variable controlling reactions, net fluxes, and sediment properties. These basic ideas and corresponding models have proved extraordinarily robust and useful. Large regions of the seafloor, however, can deviate significantly from some of the common assumptions of traditional diagenetic models, particularly along continent-ocean boundaries, where most sedimentary debris is processed. …

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Passive Tracer Reconstruction As A Least-Squares Problem With A Semi-Lagrangian Constraint: An Application To Fish Eggs And Larvae, G. G. Panteleev, B. De Young, C. S. Reiss, C. T. Taggart Jan 2004

Passive Tracer Reconstruction As A Least-Squares Problem With A Semi-Lagrangian Constraint: An Application To Fish Eggs And Larvae, G. G. Panteleev, B. De Young, C. S. Reiss, C. T. Taggart

Journal of Marine Research

A variational, data assimilation, algorithm was developed for reconstruction of a two-dimensional, nonstationary, passive tracer field in the ocean with open boundaries and a known velocity field. The observations, spatial smoothing terms and passive tracer conservation equation were included as weak constraints. The algorithm was tested with simulated, nonstationary, pseudo-oceanographic data integrated for a 7-day period. Simulations were run to determine the robustness of the algorithm and the effect of theoretical, simulated 'sampling events,' mimicking the standard oceanographic survey. We explored the sensitivity of the reconstructed tracer fields to the distribution of the pseudo-oceanographic sampling strategy, essentially an antenna problem, …

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Diffusivity And Viscosity Dependence In The Linear Thermocline, J. H. Lacasce Jan 2004

Diffusivity And Viscosity Dependence In The Linear Thermocline, J. H. Lacasce

Journal of Marine Research

We re-visit the linear model of a thermally-driven ocean in a single hemisphere, to understand dependencies on viscosity and mixing. We focus in particular on the vertical and surface velocities. In all cases, the meridional and vertical flows are intensified near the boundaries; as a result, the overturning depends on viscosity. The two types of viscosity we examine (Rayleigh damping and diffusion with the no-slip condition) yield significantly different boundary transports. This in turn can cause large changes in the surface velocities. We observe a single-gyre surface circulation with a diffusive viscosity but two gyres with the Rayleigh. We also …

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Wind-Driven Barotropic Gyre I: Circulation Control By Eddy Vorticity Fluxes To An Enhanced Removal Region, Baylor Fox-Kemper, Joseph Pedlosky Jan 2004

Wind-Driven Barotropic Gyre I: Circulation Control By Eddy Vorticity Fluxes To An Enhanced Removal Region, Baylor Fox-Kemper, Joseph Pedlosky

Journal of Marine Research

It is well known that the barotropic, wind-driven, single-gyre ocean model reaches an inertially-dominated equilibrium with unrealistic circulation strength when the explicit viscosity is reduced to realistically low values. It is shown here that the overall circulation strength can be controlled nonlocally by retaining thin regions of enhanced viscosity parameterizing the effects of increased mixing and topographic interaction near the boundaries. The control is possible even when the inertial boundary layer width is larger than the enhanced viscosity region, as eddy fluxes of vorticity from the interior transport vorticity across the mean streamlines of the inertial boundary current to the …

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Exchange Processes And Watermass Modifications Along The Subarctic Front In The North Pacific: Oxygen Consumption Rates And Net Carbon Flux, Murat Aydin, Zafer Top, Donald B. Olson Jan 2004

Exchange Processes And Watermass Modifications Along The Subarctic Front In The North Pacific: Oxygen Consumption Rates And Net Carbon Flux, Murat Aydin, Zafer Top, Donald B. Olson

Journal of Marine Research

Exchange processes along the subarctic front and the modification of subpolar water in the North Pacific are investigated using tracer data from World Ocean Circulation Experiment P14N and P17N lines. The North Pacific Current transports water on both sides of the subarctic front from the western to eastern North Pacific. During this transport, subpolar water from the western subpolar gyre becomes warmer and saltier through the main thermocline via isopycnal mixing with subtropical water. It is shown that this modified subpolar water of western origin is the primary source of well-ventilated water to the eastern subpolar gyre. The isopycnal mixing …

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Wind-Driven Barotropic Gyre Ii: Effects Of Eddies And Low Interior Viscosity, Baylor Fox-Kemper Jan 2004

Wind-Driven Barotropic Gyre Ii: Effects Of Eddies And Low Interior Viscosity, Baylor Fox-Kemper

Journal of Marine Research

Using boundary-enhanced viscosity to control the mean circulation, a simple model can be created and used for study of strong inertial effects in a western-intensified calculation. The simplicity allows for a greater number of strongly-inertial numerical experiments than computationally feasible in a general circulation model. This paper is an introduction to the behavior of this model, covering its general features. Some of the inertial phenomena, including the primary balances of the boundary current and basin interior, the temporal behavior, and the changes in the mean state across parameter space are presented. The analysis of these phenomena focuses on the effects …

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Predictability Of Lagrangian Particle Trajectories: Effects Of Smoothing Of The Underlying Eulerian Flow, Annalisa Griffa, Leonid I. Piterbarg, Tamay Özgökmen Jan 2004

Predictability Of Lagrangian Particle Trajectories: Effects Of Smoothing Of The Underlying Eulerian Flow, Annalisa Griffa, Leonid I. Piterbarg, Tamay Özgökmen

Journal of Marine Research

The increasing realism of ocean circulation models is leading to an increasing use of Eulerian models as a basis to compute transport properties and to predict the fate of Lagrangian quantities. There exists, however, a significant gap between the spatial scales of model resolution and that of forces acting on Lagrangian particles. These scales may contain high vorticity coherent structures that are not resolved due to computational issues and/or missing dynamics and are typically suppressed by smoothing operators. In this study, the impact of smoothing of the Eulerian fields on the predictability of Lagrangian particles is first investigated by conducting …

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