A newly developed in situ-measuring oceanographical probe sensing the optical index of refraction of sea water with new aspects of salinity and density determinations

This paper deals with a newly developed sensor, measuring the index of refraction in situ in the ocean, basically by use of an Abbe-half sphere refractometer cell in combination with a specially constructed fiber optical light source including a He-Ne-laser and a photo detector being capable of extreme resolution of the angle of the refracted beam. At the present stage of development a reasonable resolution of the order of 1.10^{-6} is obtained, and there is even more room for further improvement. The method is e.g. well suited for fine structure density gradient measurements and investigations of anomalies in the sea water content of dissolved substances.