TABLE 75. CHANGES OF THICKNESS OF 1936 AND 1937 ICE (IN CM) DURING THE SUMMER 

 OF 1939. REGION OF DRIFT OF THE SEDOV 



Returning to figure 79, we see that the ice thickness will be dR by the beginning of the sec- 

 ond winter . It will remain the same up to point e , when the ice freezes through . After this , it 

 begins to increase along a curve parallel to the growth curve ON until it reaches point /, corre- 

 sponding to 2R , the number of freezing degree-days by the end of the second winter, etc . 



Personally, I do not know of any quantitative data which would allow us to judge the effect of 

 the saturation of ice by water, with the exception of the Sedov observations already mentioned. 

 Hence, generalizations should be avoided until appropriate data have been accumulated. However, 

 by substituting R = 6000 and AI = 100 cm into formula (6), we get 



/max = 265 CM, 



and by substituting i? ' = 1500 into formula (7) (which is actually the case, according to the Sedov 

 observations), we get 



/max = 205 CM. 



In other words, the summer warming and the saturation of the upper layers of ice by water 

 decreases the theoretical maximum ice thickness obtained by formula (6) by 60 cm, i.e. , by a 

 rather appreciable amount. This allows us to refine Weyprecht's concept of maximum ice thick- 

 ness somewhat, as follows: the maximum ice thickness is that at which the winter regime merely 

 destroys the changes in the ice thickness and structure caused by the summer regime. 



Natural phenomena are very complicated and quantitative computations can serve only to 

 clarify the qualitative aspects of the phenomenon. We shall conduct further discussions from this 

 point of view. 



Formula (7) indicates that the maximum ice thickness depends on the number of freezing 

 degree-days R which characterize the winter regime, and on the amount of melting Aii and warming 

 R ' , which characterize the summer regime . 



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