Watermass structure in the western Indian Ocean- Part III: The spreading and transformation of Red Sea watermass

Abstract

The structure of the Red Sea Watermass (RSW) is presented. The spread of this watermass is confined to 16 N In the Arabian Sea. The depth of occurrence of its core shallows as the watermass spreads zonally and deepens towards south In the Mozambique channel. The transformation of this watermass is more rapid In the Gulf of Aden due to vertical fixing. The southern boundary of this watermass is fixed at 10 S0 where the core of RSW comes In contact with the core, of Antarctic Intermediate Water (AIW) which results in the formation of an Isohaline layer due to isopycnal mixing. Further south this watermass shows an increase in its density and Its core is noticeable at lower steric levels. The occurrence of salinity minimum in the Somali basin has been attributed to the penetration of RSW into the Subtropical Subsurface Water overlying the Antarctic Intermediate Water mass.