Section 115. Radiation and Thermal Effect of Air on thie Ice 



Let us suppose that a certain section of the sea is more or less equally covered with ice which 

 is melting in place. During the melting both the vertical and horizontal dimensions of the floes will 

 decrease. 



Let us divide the melting of the ice into two processes, which we will analyze separately; 



1. Melting of ice occurring exclusively from above on account of the heat of the atmosphere 

 and solar radiation. This is typical of the large and massive ice fields in the central arctic and, to 

 a certain degree, of fast ice before its breakup. 



2. Melting of ice occurring from the sides and below exclusively on account of the warmth of 

 the sea water adjacent to the ice which is particularly significant for floating ice composed of small 

 ice fields and floes. 



For analysis of the first case let us assume a level snow-free ice field and let us apply for our 

 purpose the method employed by Kuzmin for calculation of melting of glaciers with certain alter- 

 ations applicable for sea ice. 



Let us image a right angle vertical parallelepiped with area of horizontal sections , s , and 

 height, h. If the average temperature of the proposedly isolated volume of ice, during the period T, 

 changes from t j_tot2, then its heat contents from the same period changes by the value 



c,.S/is(/2 — /i), (1) 



where C'j = specific heat of the ice, 



6 • = density of the ice. 



On the other hand, this change in heat content of the proposedly isolated volume of ice occurs 

 through its upper and lower surfaces. 



Thus the total heat balance is equal to 



Q, + Qt,-\-Qi, (2) 



where Q^ = balance of heat flow through the upper surface, adjacent to air, 



Qu = balance of heat flow through the lower surface, adjacent to sea water, 

 Q-; = heat balance of processes going on in the given volume of ice . 



Setting the terms (1) and (2) into an equation, we obtain: 



Qs + Qi,+Qi = c,^hs (t^ — f,). (3) 



Equation (3) is the equation of the heat balance of ice in a general form. 



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