32.00 31.00 



E180°W 160° 



inn 



llilll 



c 



E180°W 160° 



Figure 34. Bathythermograms (T) and salinity traces (S) taken in the central Chukchi Sea. 



29.00"/.. 30.00 31.00 31.00 



iiiiiiiiiiA ■iihiiiiih 



N21 N19 N17E E180°W 160° 



Figure 35. Bathythermograms (T) and salinity traces (S) taken in the eastern Chukchi Sea. Double 

 trace in A represents the observed temperature when lowering and retrieving the bathythermograph. 



Several unusual features of these structures appear from the 

 bathythermograph observations. At several stations, a sub- 

 surface maximum in temperature was observed. These sub- 

 surface temperature maximums, or positive gradients, were 

 frequently observed north of 70°N near the boundary of the 

 ice. In the region of the ice pack, observations showing 

 pronounced positive gradients (fig. 33) were made from the 

 USS BOARFISH. The temperature in the warm subsurface 

 layer was 9 degrees F higher than the overlying isothermal 

 layer (fig. 33A). Repeated observations show that the layer 

 may take on different characteristics. For example, the iso- 

 thermal layer may be completely lacking, and a positive gradi- 

 ent may extend almost to the surface (fig. 33B). In some cases 



55 



