Thermal structure and flow patterns around Seychelles group of Islands (Indian Ocean) during austral autumn

Abstract

Properties of thermal structure in the upper 750 m around the Seychelles group of islands in the Indian Ocean, based on Expendable Bathythermograph (XBT) data collected in March 1984, are presented along with the inferred flow patterns. The topography of 20 degrees C isotherm suggests a broad eastward flow in the northern and northeasterly flow in the southern regions of the islands. A divergence zone with shallow thermocline in the south is visualised as a result of shear flow between opposing zonal equatorial currents-equatorial counter current in the northern and south equatorial current in the southern parts of the islands. The presence of relatively low thermocline gradients in the north, resulted due to stronger mixing, indicates the probable existence of an equatorial undercurrents