Development of a point-electrode conductivity salinometer with high-spatial-resolution for use in very-saline solutions

A conductivity probe and circuit were developed to measure salinities in sodium chloride salt gradient solar ponds. A point electrode salinometer design was chosen to give a spatial resolution of approximately 1 mm. The high spatial resolution was necessary to study the behavior of thermohaline columns in the vicinity of convective/conductive zone boundaries. The point electrode conductivity instrument was designed for use in up to 25 wt % salinities with immersion times of about 0.1 year or longer. Drift in the instrument, however, required periodic in situ calibration against the measured specific gravity of withdrawn fluid samples.