INTRODUCTION 



This is the third* of a series of reports covering 

 oceanographic researches made on a joint U. S. - 

 Canadian expedition to subarctic and arctic water 

 during the summer months of July and August 1949. 

 The observations reported here were made from 

 HMCS CEDARWOOD by scientific personnel from 

 Pacific Oceanographic Group, Canada, and U. S. 

 Navy Electronics Laboratory. The program in the 

 deep Bering Sea represents an early phase of the 

 over-all oceanographic investigations and is herein 

 discussed independently of the observations made in 

 the shallow Bering and Chukchi Seas. 



The Bering Sea is the largest adjacent sea of 

 the Pacific Ocean, and approximately half of it is 

 a deep basin with depths of around 2100 fathoms. 

 Nevertheless our knowledge of the oceanographic 

 structure and circulation of deep portions of the 

 Bering Sea has been very limited because previous 

 information was derived from surface observations, 

 bathythermograms, and relatively few oceanographic 

 stations located within 80 nautical miles of the 

 Aleutian chain. 



HMCS CEDARWOOD undertook, in the two and 

 one-half weeks available, a program of oceano- 

 graphic observations in the southeastern one-third 

 of the deep Bering Sea. The sound-velocity structure 

 obtained from these observations has been utilized 

 in the evaluation of concurrent acoustical tests. The 

 structure will also be of value for planning future 

 tests and military operations, since great-circle supply 

 routes from Unimak Pass to island bases in the 

 Aleutians would be defended in the area surveyed. 



* The two previous reports of the series were: NEL Report 

 204, Oceanographic Cruise to the Bering and Chukchi Seas, 

 Summer 1949. Part I: Sea Floor Studies, by E. C. Buffington, 

 A.J. Carsola, and R. S. Dietz, 2 October 1950 and NEL Report 

 211, Oceanographic Cruise to the Bering and Chukchi' Seas, 

 Summer 1949. Part II: Currents, by R. M. Lesser and G. L. Pickard, 

 24 October 1950. 



