case of extended cold periods so prevalent over shelf areas in the 

 southern end of the Weddell Sea, this isopycnal condition will extend 

 to the bottom. Thus, the combination of much salt from the freezing 

 process and the freezing-point temperatures probably creates water 

 dense enough to flow over the shelf and form Antarctic Bottom Water. 

 The majority of all Antarctic Bottom Wkter is believed to be formed 

 in the Weddell Sea. The density structure for a typical siommer station 

 over the Weddell shelf is illustrated in Station S.I. -24. 



Figure 4 illustrates the density profile from a group of stations 

 just outside of the Weddell Sea. As these stations are taken in open 

 areas (polynyas) within the ice pack, they may imply greater strat- 

 ification of the physical factors than actually exist. The strat- 

 ification is very likely to be much weaker between these pools of exposed 

 water. In any case, the density gradients with depth are extremely weak 

 and the presentation of this particvilar figure has been based upon 

 sigma-t differences of only 0.15 to illustrate the structure. 



12 



