The Practical Salinity Scale 1978: Fitting the data

Three equations have been fitted to new data relating the electrical conductivity of seawater to the Practical Salinity Scale 1978. These equations have been designed for the reduction of in-situ measurements of temperature, pressure, and conductivity from anywhere in the world oceans. The standard deviation of the fit is roughly equivalent to
\pm0.0015\permil
in salinity depending on the pressure at which the data is taken and, as such is commensurate with the best accuracy attainable with modern instruments.