Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 35 for “"Oceanic mixing"”.
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Rates of vertical mixing, gas exchange, and new production : estimates from seasonal gas cycles in the upper ocean near Bermuda
… that persist in spite of vertical mixing. The observed seasonal cycles of temperature, argon, helium, and oxygen are simulated with an upper ocean model. I linearize the model's response to variations in vertical diffusivity, air injection, gas exchange rate, and new production and …
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Mixing in the North Atlantic Tracer Release Experiment : observations and numerical simulations of Lagrangian particles and passive tracer
Mixing and stirring of passive tracer and Lagrangian particles in the open ocean was studied through comparison of observations from the North Atlantic Tracer Release Experiment, a numerical model, and existing theory. Based on the observed distribution of tracer during the first six months of the …
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Turbulent mixing in stratified fluids : layer formation and energetics
A turbulent mixing experiment was conducted to observe the dynamics and the energetics of layer formation along with the region of layer formation in the Reynolds number (Re) and the overall Richardson number (Rio) space. A salt stratified fluid was mixed uniformly throughout its depth with a …
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Boundary layer dynamics and deep ocean mixing in Mid-Atlantic Ridge canyons
… for several decades the total amount of abyssal mixing and upwelling required to balance the deep-water formation, but are still working to understand the mechanisms and locations—how and where it happens. From observational studies, we know that areas of rough topography are important and the …
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Mechanisms for enhanced turbulence in the Drake Passage region of the Southern Ocean
… Ocean is believed to be a hotspot for enhanced oceanic mixing. Due to the remote location and harsh conditions, few direct measurements of turbulence have been collected in the Southern Ocean. Previous studies have used indirect methods based on finestructure observations to suggest that strong …
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Mechanisms for enhanced turbulence in the Drake Passage Region of the Southern Ocean
… Ocean is believed to be a hotspot for enhanced oceanic mixing. Due to the remote location and harsh conditions, few direct measurernents of turbulence have been collected in the Southern Ocean. Previous studies have used indirect methods based on finestructure observations to suggest that strong …
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Radiation and dissipation of internal waves generated by geostrophic motions impinging on small-scale topography
… models suggest that small-scale turbulent mixing is enhanced in the Southern Ocean in regions above rough topography. The enhancement extends 1 km above the topography suggesting that mixing is supported by breaking of gravity waves radiated from the ocean bottom. In other regions, gravity …
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Mixing and general circulation dynamics : theory and observations
This thesis studies the role of cross-isopycnal mixing in general circulation dynamics, from both the theoretical and observational points of view. The first two chapters discuss some theoretical aspects of cross-isopycnal mixing in the oceans. In chapter one, an integral constraint relating the …
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Abyssal mixing from bottom boundary effects in Mid-Atlantic Ridge flank canyons
… previously neglected mechanism for abyssal ocean mixing using bottom boundary layer dynamics. Abyssal mixing and the associated upward buoyancy fluxes are necessary to balance the sinking of dense waters at high latitudes and to close the global overturning circulation. Previous studies have …
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On the role of topography and of boundary forcing in the ocean circulation
This thesis consists of two loosely related problems, both of which analyze some consequences of the failure of Sverdrup relation. In the first part, Chapters 2 and 3, the Sverdrup relation is invalidated because substantial flow is obtained at the bottom where topography exists. The eddies play an …
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Application of an inverse model in the community modeling effort results
Inverse modeling activities in oceanography have recently been intensified, aided by the oncoming observational data stream of WOCE and the advance of computer power. However, interpretations of inverse model results from climatological hydrographic data are far from simple. This thesis examines …
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Circulations and water mass balances in the Brazil Basin
Based on the Levitus atlas, we find that the application of the Montgomery streamfunction to the isopycnal surfaces induces an error which can not be ignored in some regions in the ocean. The error arises from the sloping effect of the specific volume anomaly along isopycnal surfaces. By including …
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Western South Atlantic holocene and glacial deepwater hydrography derived from benthic foraminiferal Cd/Ca and stable carbon isotope data
Today, deep waters produced in the North Atlantic are exported through the western South Atlantic. Antarctic intermediate water AAJW also enters the Atlantic in this region. Circumpolar deep water (CDW) fills the depths below AAIW and above and below northern source waters. A depth transect of …
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The production of temperature and salinity variance and covariance : implications for mixing
… A number of recent estimates of the global oceanic freshwater balance as well as the global oceanic surface net heat flux are used to investigate the effects of heat- and freshwater forcing at the ocean surface. Such forcing induces changes in both density and density-compensated temperature …
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An investigation of momentum exchange parameterizations and atmospheric forcing for the Coastal Mixing and Optics Program
This thesis presents an investigation of the influence of surface waves on momentum exchange. A quantitative comparison of direct covariance friction velocity measurements to bulk aerodynamic and inertial dissipation estimates indicates that both indirect methods systematically underestimate the …
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Dynamics of freshwater plumes : observations and numerical modeling of the wind-forced response and alongshore freshwater transport
… currents and winds influence the transport and mixing of plume waters. The first portion of the thesis considers the alongshore transport of freshwater using idealized numerical simulations. In the absence of any ambient current, the downstream coastal current only carries a fraction of the …
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Observations of turbulent fluxes and turbulence dynamics in the ocean surface boundary layer
This study presents observations of turbulence dynamics made during the low winds portion of the Coupled Boundary Layers and Air-Sea Transfer experiment (CBLAST-Low). Observations were made of turbulent fluxes, turbulent kinetic energy, and the length scales of flux-carrying and energy-containing …
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Studies of lateral dispersion in the ocean
… and the North Atlantic Tracer Release Experiment Mixing and stirring of Lagrangian particles and a passive tracer were studied by comparison of float and tracer observations from the North Atlantic Tracer Release Experiment. Statistics computed from the NATRE floats were found to be similar to …
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Cooling and internal waves on the Continental Shelf
… are initially modulated by the intense vertical mixing driven by surface cooling. The strong vertical mixing prevents the formation of geostrophic flows and inhibits the cross-shelf flux of heat. The vertical mixing is eventually suppressed by the advective transport of cold, dense water …
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Water mass distribution and Polar Front structure in the Southwestern Barents Sea
The water mass distribution in the southwestern Barents Sea, the thermohaline structure of the western Barents Sea Polar Front, and the formation of local water masses are described based on an analysis of historical hydrographic data and a recent process-oriented field experiment. This study …
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