layer about 13m thick riding atop a dense layer of cold relict water. On 

 contact with the ice the surface cooled, leaving a warm nose below. 

 This warm nose was colder and thinner, the farther into the ice the 

 station. Vestiges of the nose were still present 65-85 km from shore. 



In addition to the warm nose there was notable mesoscale 

 temperature structure, difficult to describe generally. Typically there 

 were several sharp oscillatory deviations from a smooth curve, often 

 one-sided protuberances varying from ± 0.2°C to ± 0.8°C in magnitude 

 and 2-4 m in thickness, the smaller ones most common. Still smaller 

 deviations were more numerous. These mesoscale deviations were 

 absent in the deep cold water. However there was at times a second 

 colder or warmer layer causing a broad step near bottom where the water 

 was deeper than 40 m. 



In the Beaufort Sea the warm layer had descended to 25-40 m 

 depth, its southern edge lay against the continental slope, its core was 

 at least 60 km off shore at the most northerly station. Judging from 

 Hufford's work, the core was perhaps 100 km offshore farther to the east. 

 One might speculate that the warm stream may have as much development 

 north of the core as to the south. This would suggest that warm water 

 extended another 40-60 km seaward to 100-160 km from the Beaufort Sea 

 shore . 



In this part of the Beaufort Sea the principal major feature was 

 a warm bulge with temperatures as high as 4 C and thickness 25-30 m. 

 Mesoscale structure was less pronounced than it was before the warm 

 water descended to its mid -depth position. 



III. MIZPAC 72 



A. INTRODUCTION 



MIZPAC 72 occurred at nearly the same time of year as MIZPAC 

 71, 31 July to 19 August 1972. The ship was USCGC BURTON ISLAND. 

 The cruise devoted attention exclusively to the Chukchi Sea and had 

 many of its stations farther west than the limits of the coastal current, 

 to 167° W. Closely spaced stations crossing the ice margin were 

 occupied in a number of places. It went farther north than in 1971 , to 

 73°-20' N. 



Whereas 1971 was a "normal" year for ice, 1972 was a year 

 of more than normal melting. Also, in 1972, the ice margin was rela- 

 tively compact in contrast to the fairly diffuse ice margin of 1971. 



Equipment problems were distinctly less serious. A better 

 STD was used and a shunt was in readiness to make recording possible 



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