Seasonal and inter-annual sea surface height variations of the northern Indian Ocean from the TOPEX/POSEIDON altimeter

The seasonal and inter-annual variability of the northern Indian Ocean was studied by analysing 10-day snapshots of sea surface height (SSH) data from TOPEX/POSEIDON altimeter for the period November 1992 to August 1995. The large scale SSH variations reflect the dominant seasonal signal such as the coastal currents, the upwelling zones along Somalia, Arabia and west coast of India, the Great Whirl and Southern Gyre, and eddies in the Bay of Bengal. Temporal evolution of the coastal circulation along the east and west coast of India, and offshore movement of the high (low) SSH patch during winter (summer) away from the tip of India indicates the role of remote forcings along the boundary and into the interior oceans. Inter-annual variability showed that during 1994 the winter time coastal current along the west coast of India was fully developed and intense, and upwelling signatures along Somalia and Arabia were the strongest.