INDIAN OCEAN

Speciality

he Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded by Asia—including India, after which the ocean is named—on the north, on the west by Africa, on the east by Australia, and on the south by the Southern Ocean (or, depending on definition, by Antarctica).As one component of the World Ocean, the Indian Ocean is delineated from the Atlantic Ocean by the 20° east meridian running south from Cape Agulhas, and from the Pacific Ocean by the meridian of 146°55' east The northernmost extent of the Indian Ocean is approximately 30° north in the Persian Gulf. The ocean is nearly 10,000 km (6200 mi) wide at the southern tips of Africa and Australia, and its area is 73,556,000 km² (28,350,000 mi²), including the Red Sea and the Persian Gulf.The Indian Ocean's volume is estimated to be 292,131,000 km³ (70,086,000 mi³). Small islands dot the continental rims. Island nations within the ocean are Madagascar (the world's fourth largest island), Bahrain, Comoros, Maldives, Mauritius, Seychelles and Sri Lanka. The archipelago of Indonesia and the island nation of Timor-Leste border the ocean on the east. Geography
The African, Indian, and Antarctic crustal plates converge in the Indian Ocean at the Rodrigues Triple Point. Their junctures are marked by branches of the mid-oceanic ridge forming an inverted Y, with the stem running south from the edge of the continental shelf near Mumbai, India. The eastern, western, and southern basins thus formed are subdivided into smaller basins by ridges.The ocean's continental shelves are narrow, averaging 200 kilometres (125 mi) in width. An exception is found off Australia's western coast, where the shelf width exceeds 1,000 kilometres (600 mi). The average depth of the ocean is 3,890 m (12,762 ft). Its deepest point is Diamantina Deep in Diamantina Trench, at 8,047 m (26,401 ft) deep; also sometimes considered is Sunda Trench, at a depth of 7,258–7,725 m (23,812–25,344 ft).[10] North of 50° south latitude, 86% of the main basin is covered by pelagic sediments, of which more than half is globigerina ooze. The remaining 14% is layered with terrigenous sediments. Glacial outwash dominates the extreme southern latitudes. Hydrology
Among the few large rivers flowing into the Indian Ocean are the Zambezi, Shatt al-Arab, Indus, Narmada, Ganges, Brahmaputra, Jubba and Irrawaddy River. The ocean's currents are mainly controlled by the monsoon. Two large circular currents, one in the northern hemisphere flowing clockwise and one south of the equator moving anticlockwise, constitute the dominant flow pattern. During the winter monsoon, however, currents in the north are reversed.Deep water circulation is controlled primarily by inflows from the Atlantic Ocean, the Red Sea, and Antarctic currents. North of 20° south latitude the minimum surface temperature is 22 °C (72 °F), exceeding 28 °C (82 °F) to the east. Southward of 40° south latitude, temperatures drop quickly.Surface water salinity ranges from 32 to 37 parts per 1000, the highest occurring in the Arabian Sea and in a belt between southern Africa and south-western Australia. Pack ice and icebergs are found throughout the year south of about 65° south lSSSatitude. The average northern limit of icebergs is 45° south latitude.