II. BEARING SEA - OCSANOGRAPHI 



A, General 



The Bering Sea is bounded on the north by Bering Strait, on the east 

 hj Alaska, on the west by Siberia, and on the south by the Koaandorski 

 and Aleutian Islands, In the deeper southern portion of the Bering Sea, 

 water masses are found which are similar to subarctic water masses in 

 the North Pacific Oceano To the east and north, waters over the shallow 

 shelf areas are characterized by lower salinity caused by dilution from 

 river runoff o Ice is fotind in the Bering Sea at least eight months of 

 the year, 



B, Physical Properties - Winter 1955 



Surface temperatures and salinities observed in the Bering Sea 

 during March and April are shown in Figures 3 and U» Surface tempera- 

 tures are based on observations taken with reversing thermometers at 

 oceanographic stations, supplemented by thermometer readings from bucket 

 saflrples taken while the ship was underway. Salinity values are based on 

 the surface sati5)le from the Nansen casts. Sections depicting vertical 

 distribution of tei^erature, salinity, density, and sound velocity 

 characteristics are presented in Figures 5 through 10, 



1, TeB^erature 



Surface teiqjeratures observed in the Bering Sea (Fig, 3) ranged from 

 -1,85°C at station 3 inside the ice pack to 3»U°Cr-in the open water just 

 north of Unimak Pass, Progressing northward, surface teaperatures de- 

 creased to near 0°C in the vicinity of the ice edge. 



Vertical distribution of temperature within the ice pack was nearly 

 isothermal (Figs, 5 and 6), ranging from a maximura of -1,66°C at the 

 surface to a minimum of -1,80°G at approximately 50 meters depth, except 

 at station 3 where the lowest observed temperature in the area occurred 

 at the surface. 



The temperatui^ structure across the ice boundary is shown in 

 Figures 7 through 10, In these sections, sharp horizontal surface 

 gradients are present near the boundary of the pack ice. Vertically, 

 the temperature distribution approaching and underneath the pack ice is 

 characterized by two distinct structures. In the first type (Figs, 7 

 and 8), the water is isothermal with depth, but sharp horizontal gradi- 

 ents are found at all depths from the surface to the bottom within a 

 zone near the ice boundary. Waters having these characteristics are 

 found over the shoal shelf areas where the influence of the pack ice is 

 felt to the bottom* In the second type (Figs, 9 and 10), wanner water 



Bucket temperature reading 



