The uniqueness of the Practical Salinity Scale (1978): testing the scale with natural seawaters

The scale provides a precisely defined, unambiguous method that is universally applicable to all waters for determining the practical salinity from measurements of conductivity, temperature, and pressure. In the terminology of standards, it is highly desirable to have a scale that is also unique. The authors questioned whether measurements performed on a particular water sample at different temperatures would lead to the same value of practical salinity. They have investigated this problem by examining the behavior of natural seawaters from several oceans and conclude that the PSS provides a unique scale for salinity measurements for these waters within the bounds ±0.001 in salinity