It follows from this table that in the given example, convective mixing extending to 15 m re- 

 quires no ice formation whatsoever, and in this case, the temperature of these 15 m drops from 

 t ^ = 9. 1° (column 5 of the table) to t^, = 6.4° (column 8). But if mixing reaches a depth of 

 20 m, the temperature of the entire 20 m layer not only becomes equal to the freezing point, but 

 ice 13 cm thick (column 12) forms on the sea surface. 



Further, from this table it is evident that for the vertical winter circulation to reach the bot- 

 tom (65 m) the sea surface in the examined case must release to the atmosphere 65 kg-cal/cm"^ 

 (and, during this, ice 505 cm thick must form). 



Finally, from the same table we see that with convective mixing to any level, the temperature 

 of the mixed layers ( tc) is always lower than the temperature at this same level before the start 

 of mixing ( t) which indicates the creation of a temperature inversion. The data of this table are 

 depicted graphically in figure 17. 



rct° 



1°tT> 



9m 



) 2 3 4 5 



ICE IN METERS 



Figure 17. Vertical winter circulation elements in the Bering Sea. 



In this diagram, the levels of the sea surface are plotted along the Y-axis, while the temper- 

 ature tjn< salinities 5^ and 5 , the ice thickness i, and the total amount of heat q , released by the 

 sea to the atmosphere during vertical winter circulation are plotted along the X-axis ; the corres- 

 ponding points are then connected by smooth curves. 



In the diagram we can easily determine the mean temperature from the surface to any level, 



from the t m curve. We solve the same problem for salinity from the 



S^ curve. 



The curves of 



the amount of heat and the thickness of ice formed allows us to judge these magnitudes during ver- 

 tical circulation extending to any level. The curves thus constructed allow us to answer the fol- 

 lowing questions: How much heat must be released to the atmosphere by the sea in order for the 

 vertical circulation to reach a given level? Is this accompanied by ice formation, and if so, of 

 what thickness? To what depth does circulation reach if ice of the given thickness forms? 



Figure 18 shows the isolines of the heat emission in kg-cal/cm^ of the sea's surface, with 

 vertical circulation reaching the given depth which I computed for the Barents Sea by the described 

 method. The dashed line shows the isoline of the ice thickness (in meters) which forms with mix- 

 ing to the given level. The observations were conducted by the Oceanographic Institute (Okeano- 

 graficheskii Institut) along the Kola meridian (33°30' east) in August 1931. 



It is seen from the figure how much deeper the vertical winter circulation penetrates with the 

 same amount of heat which is released to the atmosphere by the sea, e.g. , at 74° north, compared 



76 



