stopped by an ice-free expanse of open water. Later, this was noted by Sannikov in 1811 and was 

 studied by the expeditions of Anjou in 1821 to 23, Matthiesen, Brusnev and others in 1902 to 03. 

 In Wrangel's opinion, the Kolyma Lead discovered by the Wrangel Expedition in 1820 to 23 is 

 directly connected with the New Siberian Lead. 



It should be noted that in the spring of 1938, the airplanes of the Alekseev Expedition, in 

 flying to a convoy of ships which was drifting in the region to the north of the New Siberian Islands 

 (the ships Sadko, Malygin and Sedov) did not find any trace of the New Siberian Lead. However, 

 this is not surprising, because the westerly winds which had prevailed before the flights, continued 

 in this region. They closed the leads and caused a prolonged eastward drift of the convoy after it 

 had rounded Kotelnyi Island. 



The great Siberian Lead, as already pointed out, is caused chiefly by prevailing winter 

 winds, which are dispersive with respect to the edge of the pack. However, the offshore wind 

 phenomena are always accompanied by the lifting of deep water layers toward the surface of the sea 

 or even by their emergence onto the surface. In the Arctic Basin, the warm deep Atlantic waters 

 are found at a depth of 75 to 250 m from the surface, depending on the region and the general 

 thermal state of the arctic. The heat of these deep waters, which rise as a result of the offshore 

 phenomena and are mixed by convection or by the wind, aid in melting and retard ice formation. 

 Thus, the effect of the offshore phenomena is intensified and the leads become more stable. 



Akkuratov's data on the polynyas and open leads in the ice at high latitudes in the arctic are 

 very interesting. 



On 15 July 1939, during his flight to the Laptev Sea, a 10/10 ice concentration prevailed 

 from the coast to 74° north. Farther to the north, almost to 76° north, the ice concentration did 

 not exceed 2/10. On the traverse of Pronchishcheva Bay (Bukhta Pronchishcheva), open water 

 appeared. An ice edge of 2/10 concentration of small to large blocks of ice was moving eastward. 

 The open water which stretched to the meridian of the western island of Komsomolskaya Pravda 

 had extended north and northeast toward the horizon beyond the range of visibility. 



In Shokalsky Strait the ice concentration waslO/10, while at 79° 30' north and 103° east 

 open water appeared with individual accumulations of ice 1/10 to 3/10. The lead ran northeast 

 beyond the horizon. Along this parallel it extended from the 104th to 116th meridian. From there 

 the lead ran southward to Pronchishcheva Bay. 



On 27 to 28 July of that same year, open water was discovered at 78° 53' north 121° east. 

 The ice edge stretched southeast to northwest. Open water extended farther to the coast of 

 Severnaya Zemlya, passing north and south in a broad band. 



In Akkuratov's words, on 3 August 1939, ships could have passed through open water from 

 Semenovsky Island (Ostrov Semenovsky) around the New Siberian Island to Ambarchik Bay (Bukhta 

 Ambarchik), while ships plying the Laptev Strait (Proliv Lapteva) experienced difficulties. 



On 9 July 1940, Akkuratov saw much open water in the Laptev Sea at 78° north and 125° east. 

 The lead extended beyond the 130th meridian (130° east). Thus, the same open water phenomenon 

 was observed in this region, as was observed on the other in 1939. 



Further, during a flight over the East Siberian Sea on 12 to 13 July 1940, north of the Ostrov 

 Novaya Sibir up to 76° north, open water stretched northwest and northeast beyond the limits of 

 visibility. 



396 



