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 χₛ and temperature variance χₜ from conductivity
gradient spectra Ψ(k) require an understanding of the temperature–salinity gradient cross spectrum Ψₛₜ (k), which is bounded by |Ψₛₜ| ≤ √ΨₛΨₜ.
Highly resolved conductivity measurements were made using a four-point conductivity probe mounted on the
loosely tethered vertical profiler Chameleon during cruises in 1991 and 1992. Thirty-eight turbulent patches
were selected for homogeneity in shear, temperature gradient, and salinity gradient fluctuations and for clear
relationship between temperature and salinity. Estimates of χₜ and χₛ from the conductivity probe are found to
agree with independent estimators from a conventional thermistor probe
