The bathythermograph as a tool in gathering synoptic thermohaline data

A method for converting synoptic bathythermal data to density data by inferring salinity is discussed. In the depth interval covered by the bathythermograph, the salinity is obtained from mean temperature -salinity curves; these may be calculated either from historical data or from reference hydrographic stations occupied during relevant cruises. Further, on the basis of analysis of oceanographic data previously gathered in an area, the regression of the mean density field at depths below those covered by a bathythermograph on functions based on data from the bathythermograph may be obtained. These methods are exemplified for the south-east Indian Ocean but should be generally applicable in other mid-latitude regions. The aim of this paper is to provide a means for obtaining synoptic data from rapid physical oceanographic surveys.