A sharp temperature front, oriented along the south-west corner of the leading edge of a Tropical Instability Wave (TIW) warm trough, was encountered at 0°N, 140°W on November 2, 2008 and detected by a 0.45°C increase in SST that occurred over 7 s. The distinct SST signal was observed at...
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JamesN. Moum
A sharp temperature front, oriented along the south-west corner of the
The properties and evolution of nonlinear internal waves (NLIWs) depend
upon the background conditions within which waves form, propagate, and dissipate. As a result, the NLIW field on the New Jersey shelf displayed dramatic variability during the Shallow Water 2006 experiment. Wave variability was exhibited by 1) amplitudes that ranged...
This manual gives step-by-step instructions for processing raw data measured by chipod and GusT turbulence sensors. These instruments are designed and manufactured by the Ocean Mixing Group in Oregon State University's College of Earth, Ocean, and Atmospheric Sciences.
Thorough understanding of the mechanisms controlling the temperature structure in the surface mixed layer of the ocean and, in particular, accurate values of sea surface temperature are critical for properly parameterizing air-sea heat exchange and quantifying the amount of heat redistributed below the surface. It is however difficult to obtain...
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...
A low-power (<10 mW), physically small (15.6 cm long × 3.2 cm diameter), lightweight (600 g Cu; alternatively, 200 g Al), robust, and simply calibrated pitot-static tube to measure mean speed and turbulence dissipation (ε ) is described and evaluated. The measurement of speed is derived from differential pressure via...
Estimates of heat flux from direct measurements of vertical velocity-temperature
fluctuation correlations have been obtained from vertical profiles
through turbulent patches in the main thermocline. These have been compared
to more indirect flux estimates derived from dissipation rates of turbulent kinetic
energy and temperature variance. Because record lengths are limited...
Renewable energy sources are becoming increasingly important due to their low environmental impact and limitless nature. This thesis explores the design of a 250 mW permanent magnet linear generator wave energy converter to power ocean sensors. While many wave energy converters exist, this is a unique application because the wave...
The words we use to define our lives are often determined by the way we render any given moment. Every instance of writing is a moment of remembering, and a non-fiction essay gives the author free rein to unravel an instance, paint a portrait of what time has already come...
A procedure for estimating thermal variance dissipation rate χ[subscript]T by scaling the inertial-convective subrange of temperature gradient spectra from thermistor measurements on a Tropical Atmosphere Ocean (TAO) equatorial mooring, maintained by NOAA’s National Data Buoy Center, is demonstrated. The inertial-convective subrange of wavenumbers/frequencies is contaminated by the vertical motion induced...
This dissertation investigates the dynamics of the tidally modulated outflow from the Columbia River mouth using high resolution measurements of velocity, density and turbulent microstructure. At high tide, flow through the river mouth reverses from flood (onshore) to ebb (offshore). During ebb, buoyant fluid issues from the river mouth and...
Thermohaline interleaving is an important mechanism for laterally fluxing salt, heat, and nutrients between oceanic water masses. Interleaving is driven by a release of potential energy resulting from the vastly differing diffusivities of heat and salt in seawater. The flows are composed of stacked intrusions that flux more buoyant and...
A sequence of three internal solitary waves of
elevation were observed propagating shoreward along a
near-bottom density interface over Oregon’s continental
shelf. These waves are highly turbulent and coincide with
enhanced optical backscatter, consistent with increased
suspended sediments in the bottom boundary layer. Nonlinear
solitary wave solutions are employed to...
Kelvin-Helmholtz (KH) instability, characterized by the distinctive finite-amplitude billows it generates, is an important mechanism in the development of turbulence in the stratified interior of the ocean. In particular, it is often assumed that the onset of turbulence in internal waves begins in this way. Clear recognition of the importance...
A reexamination of turbulence dissipation measurements from the equatorial Pacific shows that the turbulence diffusivities are not a simple function of the gradient Richardson number. A widely used mixing scheme, the K-profile parameterization, overpredicts the turbulent vertical heat flux by roughly a factor of 4 in the stably stratified region...
Observations of currents, hydrography, and turbulence provide unambiguous evidence for hydraulic control of flow over an isolated three-dimensional topographic feature on Oregon’s continental shelf. The flow becomes critical at the crest of the bank, forming a strong supercritical downslope flow in the lower layer. Farther downstream, internal hydraulic jumps form...
At the smallest length scales, conductivity measurements include a contribution from salinity fluctuations in
the inertial–convective and viscous–diffusive ranges of the turbulent scalar variance spectrum. Interpreting these
measurements is complicated because conductivity is a compound quantity of both temperature and salinity.
Accurate estimates of the dissipation rate of salinity variance...