Mean temperature-salinty relationships in Australian waters and their use in water mass analysis

Abstract

Within a network of 2.5� (latitude) × 5� (longitude) bins in Australian waters (5�-45�s.; 105�-160�E.), mean temperature-salinity (TS) relationships have been obtained. They consist of a series of mean salinities at 2.5-degree intervals between 5 and 27.5�C. From the TS curves, at temperatures between 10 and 25�C, a region of strong meridional TS gradients is identified, centred west of the Australian mainland at 15�s. This marks the northernmost penetration of South East Indian Central Water as specified by a salinity maximum in the TS curves. The waters to the east of Australia display a uniform pattern with an upper salinity maximum associated with Subtropical Lower Water. In the whole region of study the presence of Antarctic Intermediate Water is observed as a lower salinity minimum. The TS curves are shown to be tight enough throughout the regions for useful geopotential values to be computed from temperature profiles and a mean TS relationship. Errors introduced into the calculation by this technique are less than or equal to the error involved using actual temperature and salinity data.