The time evolution of mixing in turbulent overturns is investigated using a combination of direct numerical simulations (DNS) and microstructure profiles obtained during two field experiments. The focus is on the flux coefficient Γ, the ratio of the turbulent buoyancy flux to the turbulent kinetic energy dissipation rate ϵ. In...
In spite of the effects of several form of temporal variability that tend to mask geographical patterns in turbulence intensity, our evidence indicates that the turbulence is enhanced above the equatorial undercurrent in comparison to latitudes north and south of it. This evidence consists of three meridional transects of micro-structure...
Our primary purpose in developing this instrument is to measure
vertical temperature fluctuations in the ocean to the smallest scales at
which they exist. This goal dictates the basic concept of the instrument,
as C. S. Cox saw in the 1960's. Vertical temperature changes are seen
as changes with time...
Observations of mixing over the continental slope using a towed body reveal a great lateral extent (several kilometers) of continuously turbulent fluid within a few hundred meters of the boundary at depth 1600 m. The largest turbulent dissipation rates were observed over a 5 km horizontal region near a slope...
Appearing in this issue of the Journal of Physical Oceanography are three papers that present new observations of a distinct, narrow band, and diurnally varying signal in temperature records obtained in the low Richardson number shear flow above the core of the equatorial undercurrent. Moored data suggest that the intrinsic...
High correlations between turbulent dissipation rates and high-wavenumber internal waves and the high values of turbulent dissipation associated with internal wave activity suggest that internal waves are the main direct source of mixing in the thermocline above the core of the Equatorial Undercurrent. An extensive dataset obtained using a microstructure...
In the low Richardson number shear flow above the Pacific Equatorial Undercurrent, a single vertical microstructure profile intersected the overturning crest of a packet of high horizontal wavenumber waves. The observed dissipation rates within the overturning wave were so high that if they were representative of the volume-averaged rate, the...
Although the process of restratification of the ocean surface layer at the equator following nighttime convection is similar in many ways to the process at midlatitudes, there are important differences. A composite day calculated from 15 days of consistent conditions at 140°W on the equator was compared with midlatitude observations...
A 3°N to 3°S transect of the equator at 140°15'W was made in November 1984. Vertical profiles of temperature, conductivity and turbulent dissipation were obtained at approximately 1 km intervals. Contrary to previous results, we found no obvious peak in dissipation either at the equator or clearly associated with the...
The conventional view of equatorial dynamics requires that the zonal equatorial wind stress be balanced, in the mean, by the vertical integral of “large-scale” terms, such as the zonal pressure gradient, mesoscale eddy flux, and mean advection, over the upper few hundred meters. It is usually presumed that the surface...