area within the basin. This does not necessarily 

 mean the mixing is rapid, however. The fresh 

 water inflow into the Kara Sea, while relatively 

 large, amounts to less than one-third of one- 

 percent of the volume of the basin per day. 

 Quantitatively this means approximately 3km^ 

 per day must mix thoroughly with the sur- 

 rounding water in order to maintain the aver- 

 age salinity in the area of mixing. As Sverdrup 

 has noted the effect of the fresh water runoff 

 is likely to be much more marked in summer 

 than in winter (Sverdrup, 1950). The fresh 

 water runoff when mixed with Arctic water 

 with salinity of approximately 34.5%o and tem- 

 perature — 1.7° to —1.8° C. probably forms the 

 surface water found to the north of Novaya 

 Zemlya between Franz Josef Land and the 

 Russian Continent. The formed water mass is 

 characterized by temperatures of approxi- 

 mately -1.0 to 0.5° C. and salinities of 25%o 

 to 30%o (Milligan, in press). 



CHARACTERIZATION OF WATER MASS 



Figures 60 through 81 are T-S diagrams at 

 selected stations in the Kara and Barents Seas. 

 These stations were selected with the intention 

 that the great variability of water mass charac- 

 teristics in these areas should be exemplified. 

 That the water mass characteristics in the Kara 

 Sea are extremely variable was noted by Nan- 

 sen from data taken from cruises by Nansen 

 and Nordenskiold, (Nansen, 1902). 



Figures 73 through 81 show a progressive 

 decrease in surface temperature from 6.75° C. 

 to 1.15° C. from latitude 72°00' N. to 77°37' N. 

 in the Barents Sea. The drop in temperature is 

 probably due to surface cooling as the water 

 flows northward. 



Figures 73, 74, and 75 show at first glance 

 what appear to be density inversions. However, 

 for these approximate values of temperature 

 and salinity, the lines of constant sigma-t are 

 nearly vertical indicating the density is salinity 

 controlled. Therefore, the sigma-t values ac- 

 tually increase with depth. These figures show 

 evidence of lateral mixing with a different 

 water mass. Figure 11 shows a core of rela- 

 tively high salinity water entering through the 

 eastern boundary of the survey area. The 

 34.95%o isohaline was chosen as the boundary 

 of the core. This water is probably Deep Polar 

 Water described by Nansen (Sverdrup, 1950) 



and Zenkevitch (1963) which has broken from 

 a gyre originating in a southward flow of Deep 

 Polar Water to the east of Franz Josef Land. 

 Figures 73, 74, and 75 also show a water type 

 of unknown origin in association with the 

 Deep Polar Water. This water type is charac- 

 terized by temperatures of 0.0° C. to -0.6° C. 

 and salinities of 34.75%o to 34.90%o. 



The oxygen distribution of the Kara Sea was 

 examined using Wust's core method (Wust, 

 1964), using the 9.0ml/l isopleth as the bound- 

 ary. Figure 10 shows the isopleth to be closed 

 on three sides and bounded on the fourth by 

 Novaya Zemlya. This may indicate the flow 

 of water masses with discreet characteristics 

 into the Kara Sea basin. 



A similar analysis was carried out for the 

 eastern Barents Sea, using the 8.0ml/l isopleth 

 as the boundary again as shown in Figure 10. 

 There is a tongue extending northeastward ad- 

 jacent to Novaya Zemlya. 



Figures 68 and 69, drawn from data taken 

 at stations 30 and 31 only 27.6 miles apart, 

 illustrate the extreme spatial gradients in water 

 properties which occur in the region. 



CIRCULATION OF BARENTS AND 

 KARA SEAS 



Consideration was given to attempting a 

 computation of dynamic topography in the 

 Kara Sea from the data obtained aboard GCG 

 EASTWIND. Preliminary investigations, how- 

 ever, indicated the area to be too shallow for 

 satisfactory application of the usual technique 

 of referencing each station to a level of no 

 motion. No further effort was made to compute 

 the dynamic topography. 



Previous studies have shown current speeds 

 in regions of the Kara and Barents Seas to be 

 quite low. Nansen's drift measurements aboard 

 the FRAM (Sverdrup, 1950) indicate that sur- 

 face currents in the region of the southern 

 entrance of the Barents Sea move at about 1.5 

 nautical miles per day. Milligan (in press) 

 placed current meters in two locations in the 

 vicinity of the Kara Sea. One of these was 

 placed thirty miles west of Proliv Vilkitskogo 

 at a depth of 80m. The average velocity re- 

 corded was approximately 0.15 knots in a west- 

 southwest direction. 



