12 



POLAR PROBLEMS 



water layers -and their distribution in the various parts of the North 

 Polar Sea would be of much value. While we drifted with the Fram 

 across .the Arctic Basin our deep-sea observations showed that the 

 boundaries between water layers, especially between the cold sur- 

 face layer and the warmer underlying water, were subjected to con- 

 siderable vertical oscillations. By later observations we have found 



NORTH LAT. 



Fig. 4 — Section extending from thie Faeroes through the Norwegian Sea into the basin of the North 

 Polar Sea, indicating the formation of the cold deep-water north-northeast of Jan Mayen and the dis- 

 tribution of the upper water layers. Vertical scale exaggerated 600 times. (From the author's "Spitz- 

 bergen, " Leipzig, 2nd edit., 1922, p. 208.) For location, see Fig. 3. 



The oblique, thin figures give temperature in centigrade; the vertical, heavy figures, salinity in 

 thousands. Depth in meters at the left. Symbols for water layers as follows : i , Atlantic water, salinity 

 above 35.00 0/00; 2, diluted Atlantic water flowing into the basin of the North Polar Sea, temperature 

 above o°C.;3, water of the Arctic current, temperature below 0° C, salinity below 34-00 0/00; 4, deep- 

 water with temperatures between 0° and - 0.5° C, salinity about 34-90 0/00; s, deep-water with tem- 

 peratures below - 0.5° C, salinity about 34.90 o/qq. 



that such vertical oscillations, due to subsurface boundary waves, 

 often of very considerable dimensions, probably are quite common 

 phenomena in the ocean; but they have not yet been sufficiently 

 studied methodically. From the drifting ice all movements of the 

 water — the horizontal currents as well as these vertical oscillations 

 of the layers — may be continually and carefully studied at all depths 

 in an ideal manner which is not possible in the open ocean ; and many 

 of the greatest problems of oceanography may thus be solved. 



