Table 74, computed as an example from formula (1), shows the thickness of ice of various 



ages. 



TABLE 74. THEORETICAL THICKNESSES OF ACCRETION ICE IN CM ON THE FIRST DAY 

 OF EACH MONTH COMPUTED ACCORDING TO THE AIR TEMPERATURES IN 

 1935 AND 1936 ON UYEDINENIYE ISLAND 



The freezing degree-days taken are those which were observed during the winter of 1935- 

 1936 on Uyedineniye Island. For example, the ice which had begun to form on 1 January 1936 and 

 which we call "January" in the table became 62 cm thick by 1 February, 119 cm by 1 April and 

 138 cm by 1 June. 



It can be seen from the table that there is no real difference in the ice thicknesses in 

 October, November, December and even in January. Thus, the removal or non-removal of ice 

 in the autumn has little effect on the thickness of ice encountered during the subsequent navigation 

 season. On the other hand, the spring removal (March through May) is of great importance. 

 Actually, the ice carried out at this time will be replaced by ice, 1) which is not very thick, and 

 2) which has a relatively high temperature . 



The last line of table 74 shows the average daily air temperatures for the preceeding month. 

 The data in this line and the preceding conclusions indicate the significance of ice removal during 

 spring and also of the early arrival of spring for summer navigation. 



LITERATURE: 63, 77. 



Section 87. Maximum Thickness of Perennial Ice 



Weyprecht introduced the concept of the maximum thickness of "perennial ice" accretion. 



On the basis of observations of the dependence of ice growth on the number of freezing degree- 

 days, Weyprecht found that newly-formed ice would be 209 cm thick by the end of the first winter 



225 



