Indian Ocean is different from other ocean in the pattern of its current. This is due to the size of the Indian Ocean, the position of land masses and the seasonal change in the direction of monsoon winds. This is true of the North Indian Ocean. But in the south Indian Ocean, the currents flow as in the Atlantic Ocean and Pacific Ocean.
a. North Indian Ocean currents: The north Indian Ocean currents change their direction. twice a year as result of the alternating monsoon winds greatly influence the ocean currents in summer. The current flows off from the coast of Somali as the Somali current and drifts across the Arabian Sea as the south-west monsoon drift. Finally it joins the North Equatorial current and completes a clockwise circulation.
In winter, the North east winds influence the currents. Hence the currents starting form the stair of Malacca flows along the eastern and western coasts of India as “North East Monsoon Drift” and west ward. Then it turns near the Gulf of Aden to the west flows towards the south and turns east wards near the equator, finally it joins the North Equatorial Current and completes an antilock wise circulation.
b. South Indian Ocean currents: The currents of the south Indian Ocean are not affected by the monsoon winds. So the current of the south Indian Ocean are similar to those in the southern part of the Atlantic Ocean and Pacific Ocean. In the south Indian Ocean, the South-East trade winds blow towards the west and give rise to the equatorial current, i.e. the south equatorial current.
On reaching the eastern coast of Africa, it flow southwards and is divided in two to branches, as it is obstructed by Madagascar Island. One branch enters the Mozambique current. The other branch flows eastwards of Madagascar Island and is known as ‘Madagascar current’. These two currents join again. And flow southwards as the Agulhas current. At 40 S latitude under the influence of the westerlies, it flows eastwards as West wind drift. It is also known as Indian Ocean current.
On reaching Australia, it divides into two branches, One branch turns northwards along the west coast of Australia as the west Australian current. Again turns west and North West, and finally joins the south equatorial current. The other branch moves to the southern coast of Australia and enters the Pacific Ocean.
