introduction 



This report, the fourth of the series on the cruise, is concerned with the physical 

 oceanographic studies conducted in the shallow waters of the eastern Bering and 

 Chukchi Seas.* Results of the studies of the sea floor and currents, and oceanographic 

 investigations in the deep Bering Sea are covered in separate reports. 1 ' 2 ' 3 



The dearth of oceanographic information in the Chukchi Sea and of coordinated 

 observations of the water structure to any distance on either side of the Bering Strait 

 has been brought out in previous reports. The program, therefore, was designed to 

 determine in more detail than had previously been accomplished the vertical and 

 horizontal temperature and salinity structure of the water in the approaches to Bering 

 Strait and especially in the Chukchi Sea region north of the Strait. The temperature, 

 salinity, and density of the water were to be established, and the distribution, move- 

 ments, and interaction of the water masses were to be investigated. 



The objectives were obtained by a survey from the vicinity of St. Lawrence Island 

 to Bering Strait, several surveys in Bering Strait, two surveys northward from the Strait, 

 and the return survey from Bering Strait to Unimak Pass. Because of time and operational 

 considerations, the ice was reached on only one occasion for a period of 8 hours so 

 that the coverage north of 70°N latitude, especially in the region near the ice, was 

 not as complete as desired. The operation provided good data in the areas covered 

 and valuable experience on oceanographic operations in the Arctic regions. 



previous investigations 



The complicated physical oceanography of the Bering and Chukchi Seas has 

 been investigated by various organizations. The Norwegian ship Maud obtained con- 

 siderable oceanographic data in the western Chukchi Sea between Herald Shoal and 

 Wrangel Island, but occupied only two serial stations east of 170° W. 4 



Other principal pre-World War II investigations were carried out by University 

 of Washington oceanographers in the summers of 1934, 1937, and 1938 aboard U. S. 

 Coast Guard vessels. 5,6 On these cruises, comprehensive chemical and physical oceano- 

 graphic data were obtained at serial stations giving wide coverage in the eastern 

 Bering Sea and Bering Strait, and on one occasion data were obtained along the 

 Alaskan Coast nearly to Pt. Barrow. Recent translations of Russian documents 7 furnish 



*Volume 2 of this report contains the observational data. 



1 E. C. Buffington, et al. Oceanographic Cruise to the Bering and Chukchi Seas, Summer 1949, 

 Part I: Sea Floor Studies (Navy Electronics Laboratory, Report 204) 2 October 1950. 



2 R. M. Lesser and G. L. Pickard Oceanographic Cruise to the Bering and Chukchi Seas, Summer 

 1949, Part II: Currents (Navy Electronics Laboratory, Report 211) 24 October 1950 (CONFIDENTIAL) 



3 J. F. T. Saur, et al. Oceanographic Cruise to the Bering and Chukchi Seas, Summer 1949, 

 Part III: Physical Observations and Sound Velocity in the Deep Bering Sea (Navy Electronics Laboratory, 

 Report 298) 6 June 1952 (CONFIDENTIAL) 



4 H. U. Sverdrup "The Waters on the North-Siberian Shelf" (In: The Norwegian North Polar 

 Expedition with the "Maud," 1918-1925 Scientific Results) J. Griegs, vol. 4, no. 2, 1929, pp. 34-40. 



5 C. A. Barnes and T. G. Thompson Physical and Chemical Investigations in Bering Sea and Portions 

 of the North Pacific Ocean University of Washington, 1938. 



6 J. R. Goodman, et al. Physical and Chemical Investigations: Bering Sea, Bering Strait, Chukchi 

 Sea, during the Summers of 1937 and 1938 University of Washington, 1942. 



7 G. E. Ratmanoff Explorations of the Seas of Russia (Hydrological Institute. Leningrad, Publication 

 no. 25) 1937, pp. 1-175. 



