  Ocean turbulence dissipation rate is estimated either by means of
microstructure shear measurements, or by adiabatically reordering vertical
profiles of density. The latter technique leads to the estimate of the Thorpe
scale, which in turn can be used to obtain average turbulence dissipation rate
by comparing the Thorpe scale to the Ozmidov scale. In both cases, the
turbulence dissipation rate can be estimated using single vertical profiles
from shipborne instrumentation. We present here an alternative method to
estimate the length scale of overturns by using the Ellison length scale. The
Ellison scale is estimated from temperature variance just beyond the internal
wave band, measured by moored instruments. We apply the method to high
resolution temperature data from two moorings deployed at different locations
around the Josephine seamount (North Eastern Atlantic Ocean), in a region of
bottom-intensified turbulence. The variance of the temperature time series just
above the internal wave frequency band is well correlated with the Thorpe
scale. The method is based on the time--frequency decomposition of variance
called "maximum overlap discrete wavelet transform". The results show that the
Ellison length scale can be a viable alternative to the Thorpe scale for
indirectly estimating turbulence dissipation rate from moored instruments in
the ocean if time resolution is sufficiently high. We suggest that fine
structure contaminated temperature measurements can provide reliable
information on turbulence intensity.
