higher salinity water in the estuaries and over the continental 



Bhelf to form the Northern Dilute Water. This water mass is the 



lowest in density of the three surface water masses with a value of 



less than I9 in terms of Sigma-t. Daring October the Northern 



Dilute Water attains its minimum density and is spread over a large 



portion of the northwestern bay. Furthermore^ the currents set up 



by the wind system dui'ing October are toward the southwest and carry 



the dilute water along the east coast of India almost to Ceylon. 



Here the Northern Dilute Water mixes with the Southern Bay of Bengal 



Water to form the transition water. The transition water with a 



Sigma-t value between I9 and 21 is spread over the surface of the 



central part of the bay during the fall season. The Southern Bay of 



Bengal Water is the major surface water mass of the Bay of Bengal 



and has a Sigma-t value between 21 and 22. It is the result of the 



mixing of Northern Dilute Water with all other surface waters of the 



Bay of Bengal before it reaches the southern part of the bay. The 



Southern Bay of Bengal Water is not found along the east coast of 



India during the fall season and extends across the southern and 



central part of the bay in an area just south of the transition 

 vater. 



In March the surface water is largely Southern Bay of Bengal 

 Water. This water is carried north along the east coast of India by 

 the northeast coastal current which is produced by the prevailing 

 wind system in early spring. The Northern Dilute V/ater is denser 

 during this season and is confined to the northern part of the bay. 



The greatest annual range of temperature in the Bay of Bengal 

 is found in the northern part near Calcutta where the monthly average 



^Ibid. 



29 



