The ocean currents in Indian Ocean are studied under the following sub-headings:
Ocean Currents in the Northern Indian Ocean:
1. South-West Monsoon Drift originates in summer. From June to September, the North-Equatorial current is replaced by an easterly movement of water because of the South-west Monsoon wind.
2. Somali Current is formed due to the easterly movement of water caused by the south-West Monsoon Drift in summer. It flows along the ‘horn’ in the north-east of Africa. As the water at this margin moves away eastward, upwelling of cool water originates, which makes aridity in Somali and neighboring countries.
3. North-East Monsoon Drift is formed when, in winter. The North-East Monsoon causes a westward and southward drift along the eastern coats of India and along the Arabian coast. The east-west movement of water originates.
4. North Equatorial Current is formed when, in winter, the North-East Monsoon driven water flows westward south of Sri Lanka.
Ocean Current in the Southern Indian Ocean:
1. South Equatorial Current: The South-east Trade wind originates the south Equatorial Current. This current is strengthened by water of the south Equatorial Pacific Current through the Indonesia.
2. Mozambique Current, Madagascar Current and Agulhas Current: These are all warm currents in the Indian Ocean. The south Equatorial Current after receiving the Western Australian Drift is split into two currents by the Madagascar Island, namely Mozambique Current and the Madagascar Current which combine together at the Cape of Agulhas. The current is called the Agulhas current.
3. West Australian Current is a cool current in the Indian Ocean. The North-west wind swings a part of the cold Antarctic Circumpolar Drift northwards on the Indian Ocean along the coast of Western Australia. This part of the current is called West Australian current. Finally it passes into the south Indian Equatorial Current.
4. Antarctic Circumpolar Drift circles the earth across Indian Ocean, Pacific Ocean and Atlantic Ocean as a cool current almost without interruption. It is cooled by the Antarctic ice cap.
Equatorial Counter Current, as in other oceans, flows between the North Equatorial Current and south Equatorial Current with no deflection.