ARCTIC OCEANOGRAPHY II 



along the slope outside the edge of the continental shelf north of 

 Siberia. Owing to the earth's rotation the effect of such an eastward 

 current upon the currents of the overlying water layers would be a 

 tendency to deflect them in a southerly direction, and in this manner 

 the surface current might get a less northerly and more westerly course 

 than would otherwise be the case. It has to be considered, however, 

 that the eastward current of the underlying warmer water is probably 

 very slow and that its deflecting effect upon the surface current may 

 accordingly be very small; and besides there is no such warm under- 

 current running over the continental shelf where the Jeannette and 

 the Maud drifted. 



By careful calculations Professor Valfrid Ekman has arrived at 

 the conclusion that surface currents running through regions of the 

 sea where the depths increase in the direction toward which the cur- 

 rent flows have a tendency to be deflected to the left so as to follow 

 the direction of the isobathic curves of the bottom. If this is correct, 

 it might perhaps afford an explanation of the direction in which the 

 Jeannette and the Maud drifted, as they probably had a much deeper 

 sea to the north. But the direction of the drift of the Fram cannot 

 be explained in this manner. 



Circulation of the Water 



A methodical study of the water layers and their movements in 

 the still unknown regions of the North Polar Sea will be of much 

 interest. As was discovered during the Fram expedition of 1893- 

 1896, this sea is covered by a layer, 150 to 200 meters thick, of cold 

 water with temperatures between 0° C. and - 1.9° C. and with a 

 comparatively low salinity owing to the admixture of fresh water, 

 chiefly river water from Siberia, Alaska, and Canada. Below this 

 surface layer there is a layer, some 600 or 700 meters thick, of warmer 

 and Salter water, with temperatures above 0° C. and salinities ap- 

 proaching 35 per mille. This is Atlantic water which is carried into the 

 Arctic Basin chiefly by the small branch of the Atlantic Current 

 ("Gulf Stream") running northwards along the west coast of Spits- 

 bergen (see Fig. 5). Below this warmer water there is again colder 

 water filling probably the whole basin to the bottom; its temperature 

 is between 0° C. and - 0.8° and its salinity 34.90 per mille (see Figs. 

 4 and 5). This cold deep-water originates in the northern part of the 

 Norwegian Sea, north-northeast of Jan Mayen, where it sinks down 

 from the surface, which is cooled by the radiation of heat during 

 the winter and spring. The thus cooled water runs into the Arctic 

 Basin across the probable submarine ridge between Spitsbergen and 

 Greenland (see Fig. 3).^^ A study of the condition of these various 



11 Cf. Nansen, Spitsbergen Waters, pp. 37 ff. See also idem: Spitzbergen, 2nd edit., Leipzig, 

 1922, pp. 203 ff. 



