Hydrographic Features of North Indian Ocean

Abstract

Vertical distribution of temperature, salinity and density in the first 500 meters of the north Indian ocean water has been discussed here. Vertical sections for each parameter are drawn to identity different types of water masses. Spatial distribution of these water masses in relation to the existing surface currents is also described. Two types of water masses are present to the north of the equator. The water from bay of Bengal with its characteristic low salinity (32.60-34.00%) is found upto 5 degree N and is spreading in all directions . To the south of 5 degree N the water mass is found with solinity between 35.00-35.20%. This water is existing upto 300 meters with uniform salinity along the equator. The sub-tropical salinity maximum which occurs in a thin layer just above the thermocline is observed to the north and south of equator, similar to the one encountered by defant in the atlantic ocean. The sub-tropical salinity maximum along the equator has been found to be well defined.