Islands. Bergs frequently were passed and were In almost constant 

 view on the radar screen throughout this passage, but it was not until 

 South Georgia Island was approached that any great concentration was 

 noted. Shortly after leaving South Georgia Island, a gigantic tabular 

 berg over U2 miles in length by 10 miles in width with an almost 

 continuous succession of water worn caves was passed. Dense fog en- 

 countered in this area prevented sighting of the numerous bergs which 

 were evident on the radar screen for some distance north of this point. 



The Antarctic Convergence was noted between 52°00' and 57°U1;' S. 

 As anticipated, it was found considerably north of its Pacific position. 

 Water temperatures gradually increased from 3U° to 39° F. in the South 

 Georgia area, dropped to 36° F. near the large berg, and then swiftly 

 reached kh° F, at the Antarctic Convergence. With increase in water 

 temperature, the fog gradually disappeared, the water became dark blue, 

 and a spring-like atmosphere suddenly came into being. Temperature 

 fluctuations encountered prior to crossing the convergence were caused 

 by the near presence of land masses and icebergs. 



Ice conditions encountered in the Antarctic areas traversed during 

 the ATKA's cruise may be summarized generally as follows. In the Ross 

 Sea, ice was rotten and easily penetrated but became increasingly 

 harder in consistency as the ship proceeded eastward fi^m Cape Colbeck 

 to beyond the Thurston Peninsula, South of the ship's track in this 

 area, ice appeared to be consolidated, thick, and difficult to pene- 

 trate as far toward the coast as observations could be made. In the 

 Weddell Sea, ice consistency was unpredictable from the bridge j 

 apparently hard ice was penetrated easily, while floes which appeared 

 to be rotten, often brought tho snip up with considerable impact. Ice 

 to the south and west ox the ship's track appeared to be consolidated 

 for a considerable distance. Few polynyas were noted in the Ross Sea 

 area and along the Antarctic Coast eastward; they became more frequent 

 in the Weddell Sea area. Floes were^ in general, snow covered through- 

 out. Snow coverage ranged from a few inches to several feet. Pressure 

 ridges and hummocky ice were infrequently seen, except in those areas 

 where further penetration was considered impracticable. Bergs, often 

 of large extent and mainly of the tabular type, were almost alv/ays 

 present and in certain areas attained considerable concentration and 

 close proximity. A limited amoxint of newly formed and pancalco ice was 

 encountered. Icing of the ship was noted on only a few occasions and 

 then was very slight, 



B. Bathythermograph Observations 



The results of bathythermograph casts wliile underway and while in 

 the pack ice are illustrated by the traces and profiles shown in figures 

 11 through 18, Two of the most interesting series of casts were made 

 over the location of the Antarctic Convergence in the South Pacific and 



31 



