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| Indian Ocean |
The Indian Ocean is the 3rd in size among all the oceans. About 20% of the total area of the World Ocean is occupied by it. The total surface area is 28,350,000 sq mi or 73,427,000 sq km.
It
is about 4000mi (6400 km) wide at the equator but widest between the Cape Agulhas (the southernmost tip of
Africa) and Australia.
The
northern limits of the ocean are bounded by Iran, Pakistan, India, and
Bangladesh. The eastern side of Africa is on the west cost of the ocean.
Australia and Indonesia are in the eastern side. The Atlantic is to the west, the
Pacific is to the east and the Antarctic Ocean is to the south of the Indian
Ocean.
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| Map of the Indian Ocean |
The Indian peninsula has divided the northern most
part of the ocean into two big seas – the Arabian Sea in the west and the Bay
of Bengal in the east. These two are the largest among all the marginal seas of
the Indian Ocean.
There are marginal smaller seas and gulfs of the
Arabian Sea, too. Major among these are the Persian Gulf, the Red Sea, Gulf of
Kutch, Gulf of Khambat, and the Gulf of Eden.
The Bay of Bengal has also some smaller seas within
its limits. We can mention the Andaman Sea, Malacca Srait, the Gulf of Oman,
and the Gulf of Mannar among these.
There are other smaller seas and straits like the
Laccadive Sea, Malacca Strait,Mozambique Channel etc
Islands
Islands
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| Islands of the Indian Ocean by By Nevit Dilmen [CC-BY-SA-3.0] |
Madagascar is the largest among all the islands
of the Indian Ocean (587041 sq km). It is an island country which was a part of
the Indian subcontinent from where it was detached in 88 million years ago.
Srilanka is another large island country. It is
also detached from the Indian peninsula in millions of years ago. It is
considered as a part of South Asia.
Some of the important islands or archipelagos
of the Indian Ocean are the Andaman and the Nicobar Islands, Laccadives,
Maldives, Socotra, Mauritius, Seychelles etc.
Ridges and Trenches
There is a large submarine ridge named as the
Mid-Oceanic Ridge is extended from Asia to Antarctica. The average height of
the ridge is 3000 meters or 10000 feet from the sea bottom. In some places it
is high enough to form islands.
There are some trenches along the plate boundaries on
the ocean floor. Diamantina and Sunda are the two deepest. At 8047 meter, the Diamantina deep has the highest depth.
Water
The average temperature of the water of the Indian
Ocean is the highest. It reaches 28 degree centigrade (82 degrees Fahrenheit)
in the Bay of Bengal. The temperature again goes up near the equator. But the
water becomes ice cold near the Southern sea due to the proximity of the frozen
Antarctica.
The salinity of the water varies from region to
region. Due to the high evaporation rate and low rainfalls, it is highest at 37
parts per million in the Arabian Sea. In the red sea region it crosses the 40
PPM mark.
High drainage of fresh waters from the Ganges –
Brahmaputra river system and other large rivers keep the salinity of the Bay of
Bengal at a lower limit. It is about 31 PPM.
Currents
The water of the northern parts of the Indian Ocean is
driven by the monsoon winds. The North-East Monsoon creates weak
counterclockwise water current in the Arabian Sea and a clockwise strong
current in the Bay of Bengal. The South-West Monsoon reverses those directions.
The southern part of the ocean’s surface currents is
controlled by trade winds. So, there are regular currents here like West
Australian Current, South Equatorial Current, West Wind Drift, Mozambique
Current, etc.
Climate
We can divide the area of the Indian Ocean into
several climate zones. In the northern part is the famous Monsoon zone. There
are also Trade Wind Zone, Sub Tropical and Moderate Zone, and the Sub-Antarctic
Zone.
The Monsoon Zone is the area above the 10 degrees
South latitude. It is characterized by the semiannual reversing Monsoon winds.
The intense heat of the south Asian summer is one of the reasons of the
creation of the Monsoon winds. It brings a season of rainfall in the month of
Jun to August.
The Trade Wind Zone is characterized by its regular
flow of winds and unchanging wind directions. It lies between 10 to 30 degrees
S. In December to June, many cyclones generate in this area, mainly near the
east of Madagascar.
The 3rd Subtropical zone is situated in the
Southern hemisphere. 30 to 45 degrees South is the boundary of this zone. It is
controlled by light to moderate westerly winds.
The subantarctic zone is known for its low
temperature. The ocean below the 45 degrees south falls in this zone. Floating
ice chunks can be found here during the winter seasons.
Economy
The
Indian Ocean connects with the world’s major petroleum producing regions with
the major petroleum users. The petroleum from the Arab countries and from Iran goes
to Europe, Americas and China via this ocean routes.
Offshore
petroleum can be harnessed from the shores of Arab countries, India, Pakistan,
Srilanka, Indonesia, South Africa, and Thailand. These hydrocarbon sources will
run the human machines for a long time.
Ports
There
are many important ports to carry out maritime trade and commerce in the Indian
Ocean. Mumbai port of India opens in the Arabian Sea. Some other major ports of
Indian subcontinent are Marmagao, Kolkata, Port Blair, Karachi, Gwadar, Chennai, Tuticorin, Visakhapatnam,
Paradip, Chirragong, Colombo, Galle etc.
The
key to the red sea and the trading between Europe and Asia is controlled by the
Aden port of Yemen. Singapore controls the trade route between Europe, South
Asia, China, and Japan in the Strait of Malacca.
Mombasa,
Zanzibar and Durabn are some of the major ports of the African shore of the
Indian Ocean. Some other such important ports are Port Luis, Beira, Richard’s
Bay, and New London etc.
There
are many Asian ports beside the ocean. Some of the major ones are Muscat,
Yangon, Jakarta, and Dubai etc.
