needed to determine accurately the direction and plane of movement of this warm 

 intrusion into the Ross Sea. Present data indicate a southwest and westward move- 

 ment. Bottom relief without doubt exerts a major influence. 



The extent of this penetration was not well established prior to this survey. 

 Present data indicate that in modified form, at least, it invades much of the Ross 

 Sea and can be detected as far south as the western and central portions of the Ross 

 Ice Shelf (Figs. 6, 7, and 8), and westward approaching Victoria Land Coast (Fig .9). 



(3) Shelf Water is the coldest, most saline, and most dense water mass in the Ross 

 Sea . It comprises the major portion of the water column in the west and southwest 

 regions, generally becoming a lesser component seaward (Figs. 10 and 7). 



Table 2 lists the water types as they exist in the Ross Sea and presents their 

 identifying properties. 



TABLE 2. WATER TYPES OF THE ROSS SEA 



Temperature Salinity Sigma-t Oxygen 



(^'C) (%o) (ml/I) 



Upper Water 

 Antarctic Sur- -1 .75 - +1 .50 33.50 - 34.50 27.00 - 27.65 7.50 - 8.50 

 face Water 



Winter Water -1 .70 - -1 .90 34.15-34.45 27.50-27.75 6.30-6.80 



Circumpolar Water + 1.50- +0.50 34.60-34.75 27.70-27.90 4.30-4.80 



Shelf Water -1.80 --2 .05 34.75-35.00 28.00-28.20 6.00-6.50 



This proposed classification provides a helpful guide in the study of oceanography 

 in this area. Transition zones exist between all the various water types. The change 

 may be great over a short vertical distance, as for example that of the temperature 

 and the oxygen between Winter and Circumpolar Water (Fig. 11). Changes also may 

 be gradual like the salinity change between modified Circumpolar Water and Shelf 

 Water (Fig. 12). 



B. Descriptive Oceanography of the Ross Sea 



A resident mass of Upper Water occupies the southeastern Ross Sea . A layer 

 of Antarctic Surface Water extends downward to about 30 to 100 meters. Below 

 this layer there is a well-defined transition into Winter Water which extends to 

 bottom. The layer of Antarctic Surface Water at Station G-01 near the Ross Ice 

 Shelf becomes thinner to the north and west at Stations G-02 and B-16 (Figs. 13, 

 14, and 15). Circumpolar Water intrudes and mixes with Winter Water near the 



12 



