ENERGY-CONTAINING SCALES OF TURBULENCE IN THE OCEAN THERMOCLINE

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 f ormulations are tested using coincident measurements of the relevant p roperties of both energy-containing and dissipation scales of stratifi ed turbulence in the ocean's main thermocline obtained from a vertical microstructure profiler. It is found that energy-containing scale est imates of both dissipation rate and heat flux compare favorably with d issipation scale estimates. Since the energy-containing scales are man y times greater than the dissipation scales, the measurement constrain ts on these new estimates are considerably less strict than for dissip ation scale estimates of the same quantities. These observations also suggest that the timescale for viscous decay of turbulent motions is g reater than that for diffusive smoothing of scalar fluctuations. It is argued that this is consistent with current estimates of mixing effic iencies.