The characteristics of the currents of the Indian Ocean are quite dierent from those of Paciand Atlantic Oceans. This is due to the fact that it is just half an ocean and is completely land-locked in the north. The currents of the northern Indian Ocean change their direction due to seasonal change in the direction of the monsoons. The current aected by monsoons is known as the ‘Monsoon Drift’.
The southern part of the Indian Ocean extends right upto the Antarctic Coast and is not inuenced by seasonal changes. The general pattern of circulation is simple and is anti-clockwise like that of the other southern oceans.
The currents of the North Indian Ocean can best be studied with reference to seasonal changes:
In winter, the north equatorial current is under the inuence of north-east monsoon and blows from east to west. This is known as North-East Monsoon DriIt starts from the Strait of Malacca and was along the coast of Bay of Bengal. Aer crossing Sri Lanka, it was along the coast of Arabian Sea and turns southwards. From there it travels from west to east as Counter Equatorial Current and completes the anticlockwise circulation.
During summer, a strong current flows from west to east which completely obliterates the North Equatorial Current during this season. It is due to the effects of the strong south west monsoon and the absence of the North-East Trades. There is no counter Equatorial Current at this time of the year. Thus, the circulation of water in the northern part of the ocean is clockwise during this season.
The circulation of currents of South Indian Ocean is similar to that of South Pacific and South Atlantic Oceans. Following scheme explains these currents:
South Equatorial Current
Like other oceans, Indian Ocean has south equatorial current wing parallel to the equator from east to west.
The South Equatorial Current divides itself into two branches on reaching Madagascar. One of them ows through the Mozambique channel between Mozambique and Madagascar coasts. This is a warm current and is known as warm Mozambique Current.
The other branch of the South Equatorial Current flows along the east coast of Madagascar and is known as Madagascar Current.
In the south of Madagascar Island, the Mozambique and the Madagascar currents join with each other. After the conuence of these two currents, it is known as the Agulhas Current. It still continues to be a warm current till it merges with the west wind drift.
West Wind Drift
The west wind a cold current which was from west to east and reaches the southern tip of the west coast of Australia.
West Australian Current
On reaching Australia, the west wind divided into two branches. One of the branches moves northwards along the west coast of Australia and is known as West Australian Current. It ultimately joins the south equatorial current and completes the counter clockwise circuit in the South Indian Ocean.