The Indian Ocean is the third largest ocean on our planet. It is just slightly smaller than the Atlantic, covering about 20% of the Earth’s water surface. It is bounded on the north by Southern Asia (including the Indian subcontinent, after which it is named), on the west by the Arabian Peninsula and Africa, on the east by the Malay Peninsula, the Sunda Islands, and Australia and on the south by the Southern Ocean.
One component of the all-encompassing World Ocean, the Indian Ocean is outlined from the Atlantic Ocean by the 20° east meridian running south from Cape Agulhas and from the Pacific by the 147° east meridian. The northernmost extent of the Indian Ocean is approximately 30° north latitude in the Persian Gulf.
This ocean is nearly 10,000 kilometres (6,200 miles) wide at the southern tips of Africa and Australia and its’ area is 73,556,000 square kilometres (28,400,000 sq miles) including the Red Sea and the Persian Gulf.
The oceans volume is estimated to be 292,131,000 cubic kilometres (70,086,000 sq miles). Small islands dot the continental rims. Island nations within the ocean are Madagascar, the world’s fourth largest island, Comoros, The Seychelles, Maldives, Mauritius and Sri Lanka. Indonesia also borders the Indian Ocean.
The oceans continental shelves are narrow, averaging 200 kilometres (125 miles) in width. An exception is found off Australias western coast, where the shelf width exceeds 1,000 kilometres (600 miles). The average depth of the ocean is 3,890 metres (12,760 feet). Its deepest point, is in the Diamantina Deep close to the coast of Perth, south west Western Australia, and has been measured at 8,047 metres (26,401 feet) deep.
The Indian Ocean is divided into three major sections by the Mid-Oceanic Ridge which runs from Asia to Antarctica in an upside down Y shape with the stem running south from the edge of the continental shelf near Mumbai, India. The sections are, the African, the Antardis, and the Australasian. Many deep sea basins are enclosed by the Mid-Oceanic Ridge. The deepest among these (after the Diamantina Deep) is the Java Trench which reaches a depth of 7,450 metres.
North of the Equator, the climate is affected by a monsoon wind system. Strong northeast winds blow from October until April and from May until October south and west winds prevail. In the Arabian Sea the violent monsoon brings rain to the Indian subcontinent. In the southern hemisphere the winds generally are milder, but summer storms near Mauritius can be severe. When the monsoon winds change, cyclones sometimes strike the shores of the Arabian Sea and the Bay of Bengal.
Among the few large rivers flowing into the Indian Ocean are the Zambezi, Arvandrud/Shatt-al-Arab, Indus, Ganges, Brahmaputra, and Ayeyarwady River. Currents are mainly controlled by the monsoon. The Indian Ocean has two water circulation systems. The northern system circulates in a clockwise direction except during the winter monsoon season when the currents are reversed. Low atmospheric pressure over southwest Asia from hot, rising, summer air results in the southwest monsoon and clockwise winds and currents. High pressure over northern Asia from cold, falling, winter air results in the northeast monsoon and anticlockwise winds and currents. In the southern portion of the Indian Ocean, currents travel in a anticlockwise direction.
The main important factors of the Indian Ocean has been as a trading route between Africa and Asia. Petroleum, extracted mainly from the Persian Gulf area is also important. Somewhat warm surface temperatures keep the growth of phytoplankton low, which restricts the population of ocean life. Fishing is only done at the means level to aid livelihood.
The oceans importance as a transit route between Asia and Africa has made it a scene of conflict. Because of its size, however, no nation had successfully dominated most of it until the early 1800’s when Britain controlled much of the surrounding land. Since World War 2, the ocean has been dominated by India and Australia.