Salinity maxima in the upper 1000 metres of the North Indian Ocean

The comprehensive hydrological data from cruise 31 of R.S. Vityaz in the north Indian Ocean have been used to identify all salinity maxima of the upper 1000 m. On the basis of density differences these salinity maxima have been grouped into five water masses. Three of these have been named according to their assumed origin; Red Sea, Persian Gulf, and Arabian Sea. The other two can not as yet be assigned origins, although one is confined largely to the northern part of the Arabian Sea and the other to the equatorial region of the Indian Ocean. Paths of flow of these water masses to the south and east have been established from salinity charts. Submarine topography in the Madagascar-Seychelles and Maldive-Chagos regions provides an explanation for the diversion and separation of the flow paths of these water masses.