Indian Ocean Water masses
• Characteristics of water masses of Indian ocean is different from other
oceans because of its geographical position and climatic conditions.
• Indian ocean has a assymetric shape due to the presence of Asian land
mass.
• Indian ocean has a different precipitation pattern. This causes large
amount of river runoff.
• Waters from Red sea and Persian Gulf influence waters of Arabian sea.
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Indian Equatorial Watermass
• Found at north of 10S.
• T = 4 to 17C, S = 34.9 to 35.25psu
• Extends 200 to 2000m.
• Also called as North Indian High Salinity Intermediate water.
• Formed by Australasian water and Indian central water.
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Indian Central water
• The high saline ICW is found in the upper layers of south Indian ocean
between 10 and 40S.
• Formed by sinking in the subtropical convergence.
• Salinity is high (35 psu) due to excess evaporation over precipitation.
• Extends upto 1000m.
• Straight line TS curve. T = 8 to 15C, S = 34.6 to 35.5 psu.
• Spreads towards north and carried by SEC to west.
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Arabian Sea High Salinity Watermass
• Forms at surface of north Arabian sea.
• Influenced by monsoon
• Chacterized by high salinity due to high E-P.
• Fows southwards.
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Persian Gulf water
• Warm and saline.
• Enters Arabian sea via Gulf of Oman.
• Spreads to the northern Arabian sea with a salinity maximum at a
depth of about 500m.
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Red Sea water mass
• Warm and saline enters to Arabian sea via Gulf of Aden.
• Reaches upto 18N in the Arabian sea.
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Deep watermasses
• Antarctic Intermediate water is found below central water.
• Bottom waters are from Antarctic /Atlantic origin.
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