south of 75° north and east of 40° east is a region of sub-polar ice abundance, while north of 75° 

 but east of 40° is a region of polar ice abundance. 



Figure 177 shows the position of the ice edge in the Greenland and Barents Seas in May 1936, 

 according to observations of Soviet vessels, while figure 178 shows the position in October to 

 December of the same year. 



30' 20' 



jr 



SI. 



10' 



20' 



30° 



40° 



SO' 



60° 



70° 



W 



?^^i?#'^ 



///;////<^/ 



W'^//'^///,/^ 







Figure 177. Ice conditions in the Greenland and Barents Seas, May 1936. 



The ice conditions on the course of the Northern Sea Route in mid-September 1936 are shown 

 in figure 179. 



In these figures the numbers in circles indicate the quantity of ice in tenths. The nature of 

 the ice (size of floes) is shown by conventional symbols. 



Figure 179 is more or less typical for ice conditions in the seas along the Northern Sea Route 

 in that it clearly shows the two ice regions of this route which determine its passability. The first 

 is the region of Vilkitski Strait. The Norwegian current and the drainage of the Ob and Yenisei 

 rivers have their effect to the west of it, while east of it is a region exposed to the influence of the 

 Lena river. The second ice region is in Long Strait. West of it is the Lena region, comparatively 

 mild In respect to ice, while east of it is the area under the influence of the Pacific Ocean current 

 entering through the Bering Strait. 



447 



