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 23 for “"diapycnal mixing"”.
-
Diapycnal mixing transience and the meridional overturning circulation
Diapycnal mixing of ocean waters is crucial to the dynamics and associated heat transport of the meridional overturning circulation, yet uncertainty exists regarding the distribution and physical mechanisms of this mixing. This study uses a highly-idealized, single-hemisphere model of …
-
Diapycnal Mixing and Mass Transfer in Western Boundary Currents
… of nine isopycnal layers reveal significant diapycnal mixing between upper-thermocline and surface waters in the sector of the Stream between the Florida Straits and the Mid-Atlantic Bight. A two-box model of the nutrient-depleted surface layers (σ<sub>t</sub> < 26.8) and the nutrient-rich …
-
The Role of diapycnal mixing in coupled atmosphere-ocean general circulation models
The value of ocean diapycnal diffusivity (v) sets the rate at which dense bottom water can be mixed<br/>up through the stratified water column and thus plays an important role in the meridional overturning<br/>circulation (MOC). Previous idealised experiments and simplified theory suggest that the …
-
Mixing in stably stratified turbulent flows: improved parameterizations of diapycnal mixing in oceanic flows
Mixing of fluid with different properties across a gravitationally stable density interface, due to background turbulence is an ubiquitous phenomenon in both natural and engineered flows. Fundamental understanding and quantitative prediction of turbulent mixing in stratified flows is a challenging …
-
A study of diapycnal mixing in the Southern Ocean using a tracer release experiment and numerical models
The Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) includes a tracer release experiment and microstructure programme with the aims of diagnosing the strength and variability of mixing in the Southern Ocean. Here numerical models are used to advect and diffuse a tracer in …
-
The roles of mixing, geothermal heating, and surface buoyancy forcing in ocean meridional overturning dynamics
… system's scaling behavior, the consequences of diapycnal mixing location, the impact of deep buoyancy fluxes, and the importance of the surface restoring timescale are considered. As required by advective-diffusive balance, upwelling across isopycnals in low latitudes occurs where diapycnal …
-
The production of temperature and salinity variance and covariance : implications for mixing
… fluxes, leading to important consequences for mixing in the ocean interior. In a stratified ocean, mixing processes can be either along lines of constant density (isopycnal) or across those lines (diapycnal). The contribution of these processes to the total mixing rate in the ocean can be …
-
The production of temperature and salinity variance and covariance : implications for mixing
… fluxes, leading to important consequences for mixing in the ocean interior. In a stratified ocean, mixing processes can be either along lines of constant density (isopycnal) or across those lines (diapycnal). The contribution of these processes to the total mixing rate in the ocean can be …
-
Hydrography and flow in the rift valley of the Mid-Atlantic Ridge
… axes of midocean ridges include high rates of diapycnal mixing associated with the rough topography and high-temperature hydrothermal circulation, a major source for a number of chemical constituents of the ocean.<br/><br/>Physical data sets from the rift valley of two connected segments of the …
-
Driving the ocean's overturning : an adjoint sensitivity study
… overturning circulation to surface forcing and mixing on climatological time scales. An adjoint model is used to gain new insights into the spatial characteristics of the sensitivity patterns. Adjoint models provide the sensitivity of a diagnostic, often called cost function, to all model …
-
Diapycnal advection by double diffusion and turbulence in the ocean
Observations of diapycnal mixing rates are examined and related to diapycnal advection for both double-diffusive and turbulent regimes. The role of double-diffusive mixing at the site of the North Atlantic Tracer Release Experiment is considered. The strength of salt-finger mixing is analyzed in …
-
Diapycnal advection by double diffusion and turbulence in the ocean
Observations of diapycnal mixing rates are examined and related to diapycnal advection for both double-diffusive and turbulent regimes. The role of double-diffusive mixing at the site of the North Atlantic Tracer Release Experiment is considered. The strength of salt-finger mixing is analyzed in …
-
Aspects of southern ocean transport and mixing
… have shown that the spatial variability of diapycnal diffusivity, which represents the rate at which deep water returns to shallower depths by means of turbulent diapycnal mixing, is a critical factor controlling the strength and structure of the circulation. Efforts are therefore ongoing to …
-
Triple oxygen isotopes and oxygen/argon ratio measurements to enhance coastal and open ocean production/respiration comparisons
… in the SAG were higher than published results. Diapycnal mixing was found to contribute about 20% to apparent mixed layer N in both gyres and to G in the NAG. In order to achieve these results, a gas extraction line was built and tested. A method to halt biological activity in triple oxygen …
-
Effects of ocean turbulence on the large-scale stratification and Small-Scale Particle Distributions
… of cold water from the abyss and the downward mixing of heat by turbulence. At smaller scales, however, the upwelling and mixing exhibit tremendous spatial variability, belying the simple structure of the stratification. Observations of mixing are too sparse to extrapolate accurately to large …
-
Mechanisms of Subantarctic Mode Water re-emergence in a hybrid-coordinate global GCM
… upwelling mechanisms exists though. Regridding mixing driven by the Ekman pumping effect and shear-induced mixing dominate SAMW upwelling in the equatorial oceans. Induction at isopycnal outcrops is critical to SAMW upwelling in the high-latitude North Atlantic. It is found that SAMW has little …
-
Modelling large scale ocean circulation : the role of mixing location and meridional pressure gradients for the Atlantic overturning dynamics
… evolved around what are its driving mechanisms: diapycnal mixing and Southern Ocean winds. This work aims at clarifying what sets the strength of the Atlantic overturning components in an ocean general circulation model and discusses the role of spatially inhomogeneous mixing, numerical diffusion …
-
Turbulence in the sea ice impacted Southern Ocean and its implications for primary production and carbon export
… by enhancing stratification. Secondly, turbulent diapycnal mixing and double diffusive convection (0.1-1 m scales) drive the warming of the subsurface winter water, therefore mediating fluxes between the ocean interior and surface. Finally, phytoplankton respond favourably to larger volume sea ice …
-
Time-Lapse Volumetric Seismic Imaging of a Major Oceanic Front and Submesoscale Coherent Vortices at South Atlantic Ocean
… of thermohaline structures and ocean mixing. Between December 2012 and April 2013, a three-dimensional (3-D) seismic survey was carried out at the Brazil-Malvinas Confluence of the South Atlantic Ocean. Each individual seismic swath is approximately 140 km long and 600 m wide. The …
-
Lagrangian study of the Southern Ocean circulation
… which includes the investigation of the role of diapycnal mixing and the impact of short and long time variability in the flow. Although we show that the flow of particles in the 3-D model is predominantly isopycnal, we find that particles that are forced to remain on isopycnals lead to approx. …
Page 1 of 2