Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1992 Oceanic profiles of temperature, salinity, horizontal velocity, rate of dissipation of turbulent kineti...
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Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
1992
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/5484 2023-05-15T17:45:47+02:00 Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion Polzin, Kurt L. Northwest Atlantic Subtropical Front 1992-09 application/pdf https://hdl.handle.net/1912/5484 en_US eng Massachusetts Institute of Technology and Woods Hole Oceanographic Institution WHOI Theses https://hdl.handle.net/1912/5484 doi:10.1575/1912/5484 doi:10.1575/1912/5484 Turbulence Internal waves Wave functions Endeavor (Ship: 1976-) Cruise EN141 Thesis 1992 ftwhoas https://doi.org/10.1575/1912/5484 2022-05-28T22:58:40Z Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1992 Oceanic profiles of temperature, salinity, horizontal velocity, rate of dissipation of turbulent kinetic energy (ε) and rate of dissipation of thermal variance (χ) are used to examine the parameterization of turbulent mixing in the ocean due to internal waves. Turbulent mixing is quantified through eddy diffusivity parameterizations of the mass (Kρ; Osborn, 1980) and heat fluxes (Kτ; Osborn and Cox, 1972) in turbulent production/dissipation balances. Turbulence in the ocean is generally held to result from the occurrence of shear instability in regions where the Richardson number is locally supercritical (i.e. Ri ≤ 1/4), permitting the growth of small-scale waves which break and result in turbulent mixing. The occurrence of shear instability results from the local intensification of the shear in the internal wave field. The energy dissipated in such events is provided by the energy flux to higher wavenumber due to nonlinear wave/wave interactions on scales of 10's to 100's of meters. In turn, the strength of the wave/wave interactions depends generally on the energy content of the internal wave field, which can vary considerably over even larger scales due to the presence of topography or background flows. The magnitude of turbulent mixing is linked to internal wave dynamics by equating the turbulent dissipation with the energy flux through the vertical wavenumber spectrum under the priviso that the model spectrum which forms the basis for the analysis is statistically stationary with respect to the nonlinear interactions. Dynamical models (McComas and Muller, 1981; Henyey et al., 1986) indicate that the Garrett and Munk (GM; Munk, 1981) spectrum is stationary. Observations from the far field of a seamount in a region of negligible large-scale flow were examined to address the issue of the buoyancy scaling of ε. ... Thesis Northwest Atlantic Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Munk ENVELOPE(-95.993,-95.993,55.979,55.979) Osborn ENVELOPE(-120.378,-120.378,56.604,56.604) Woods Hole, MA |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Turbulence Internal waves Wave functions Endeavor (Ship: 1976-) Cruise EN141 |
spellingShingle |
Turbulence Internal waves Wave functions Endeavor (Ship: 1976-) Cruise EN141 Polzin, Kurt L. Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion |
topic_facet |
Turbulence Internal waves Wave functions Endeavor (Ship: 1976-) Cruise EN141 |
description |
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1992 Oceanic profiles of temperature, salinity, horizontal velocity, rate of dissipation of turbulent kinetic energy (ε) and rate of dissipation of thermal variance (χ) are used to examine the parameterization of turbulent mixing in the ocean due to internal waves. Turbulent mixing is quantified through eddy diffusivity parameterizations of the mass (Kρ; Osborn, 1980) and heat fluxes (Kτ; Osborn and Cox, 1972) in turbulent production/dissipation balances. Turbulence in the ocean is generally held to result from the occurrence of shear instability in regions where the Richardson number is locally supercritical (i.e. Ri ≤ 1/4), permitting the growth of small-scale waves which break and result in turbulent mixing. The occurrence of shear instability results from the local intensification of the shear in the internal wave field. The energy dissipated in such events is provided by the energy flux to higher wavenumber due to nonlinear wave/wave interactions on scales of 10's to 100's of meters. In turn, the strength of the wave/wave interactions depends generally on the energy content of the internal wave field, which can vary considerably over even larger scales due to the presence of topography or background flows. The magnitude of turbulent mixing is linked to internal wave dynamics by equating the turbulent dissipation with the energy flux through the vertical wavenumber spectrum under the priviso that the model spectrum which forms the basis for the analysis is statistically stationary with respect to the nonlinear interactions. Dynamical models (McComas and Muller, 1981; Henyey et al., 1986) indicate that the Garrett and Munk (GM; Munk, 1981) spectrum is stationary. Observations from the far field of a seamount in a region of negligible large-scale flow were examined to address the issue of the buoyancy scaling of ε. ... |
format |
Thesis |
author |
Polzin, Kurt L. |
author_facet |
Polzin, Kurt L. |
author_sort |
Polzin, Kurt L. |
title |
Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion |
title_short |
Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion |
title_full |
Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion |
title_fullStr |
Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion |
title_full_unstemmed |
Observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion |
title_sort |
observations of turbulence, internal waves and background flows : an inquiry into the relationships between scales of motion |
publisher |
Massachusetts Institute of Technology and Woods Hole Oceanographic Institution |
publishDate |
1992 |
url |
https://hdl.handle.net/1912/5484 |
op_coverage |
Northwest Atlantic Subtropical Front |
long_lat |
ENVELOPE(-95.993,-95.993,55.979,55.979) ENVELOPE(-120.378,-120.378,56.604,56.604) |
geographic |
Munk Osborn |
geographic_facet |
Munk Osborn |
genre |
Northwest Atlantic |
genre_facet |
Northwest Atlantic |
op_source |
doi:10.1575/1912/5484 |
op_relation |
WHOI Theses https://hdl.handle.net/1912/5484 doi:10.1575/1912/5484 |
op_doi |
https://doi.org/10.1575/1912/5484 |
op_publisher_place |
Woods Hole, MA |
_version_ |
1766149039667019776 |