summers, varying substantially in temperature. Its apparent absence in 

 some years may be due to station distribution. 



The general situation in the costal area of the northern Chukchi 

 and the western Beaufort Seas may be summarized by means of a single 

 diagram. This time^ sound velocity will be shown at Stations 46, 66, 74, 

 and 114 in Fig. 28. Detail may vary greatly with time and position. 

 Station 46 with two sharply interfaced layers is typical of the coastal 

 current distinctly south of the ice. There is little finer structure. Sta- 

 tion 66 shows the effect of considerable surface cooling. It is in the 

 Barrow Sea Valley, so shows the effect of cold high- salinity water near 

 the bottom. This station is fairly representative of all the stations 

 further into the ice except for depth. It has a residual warm nose, 

 deeper than the original warm-water layer and it has considerable finer 

 structure. Toward the south and southwest from Station 66 larger noses 

 exist caused by moderate surficial cooling of a structure like Station 46. 

 Station 74 represents the beginnings of the entry of the warm current 

 into the Arctic Basin. It is well cooled at the surface and has a tempera- 

 ture maximum at 20 meters where the core of the warm water has de- 

 scended to a deeper equilibrium density level. This station probably 

 has finer structure which does not show because the RS5 was used. 

 Finally, Station 114 is probably typical of the water along the Beaufort 

 Sea slope. The warm core has descended to 30 meters and colder water 

 is beginning to appear underneath. The fine structure is mild. 



Although there are many stations at which only RS5 data are 

 available, often obscuring fine structure, there are enough continuous 

 temperature traces to strongly suggest that there is at least moderate 

 meso scale structure throughout the zone of active interaction of the 

 coastal current and ice. This extends through the entire area surveyed, 

 from the southern boundary of the ice to the more northerly boundary 

 between Stations 91 and 103. In the Beaufort Sea the warm water is 

 no longer near enough to the surface to interact actively with the ice 

 and mesostructure is mild. 



E. CONCLUSIONS 



The data taken in MIZPAC 71 are nearly everywhere dominated 

 by the warm coastal current having its origin in Bering Strait. This cur- 

 rent turns eastward just beyond the turn of the 10-fathom depth curve 

 about 25 km northwest of Pt. Barrow and continues to beyond 152°W, the 

 limit of adequate sampling. Hufford has shown it extending to at least 

 I47°W and shows it present in historical data. It, therefore, is present . 

 in the Beaufort Sea most of the time in the warmer parts of the summer. 



Before encountering ice the warm water, at about 6 C, was a 



43 



