Observed low-frequency currents in the deep mid-Arabian Sea

Abstract

Current meter records from approximately 1000 and 3000 m at three moorings with a zonal separation of about 5° along the 15°N latitude in the mid-Arabian Sea during May 1986 to May 1987 have been used to describe the low-frequency currents in the area. Although the spectra for the six time series have similar shapes, their energy levels differ. There was no significant coherence between upper and the lower currents at any mooring, nor between currents at adjacent moorings. Energies dropped from the west to the east both at the upper and the lower levels, but the drop was much larger in the deeper currents. In fact, the energy in the deeper currents for periods from 1 to 4 weeks was higher than that at the upper level at the western mooring, marginally higher at the central mooring, and not significant at the eastern mooring.