e = pressure of saturated water vapor in mc calculated for the surface temperature and 

 salinity of the ocean, 



e = pressure of water vapor in mc observed at a height of 6 m above the sea surface, 



w = wind speed in m/sec reduced to 6 m above the sea surface. 



It is evident that this formula can be adapted for the calculation of heat loss by the sea to 

 evaporation — namely, 



Q= -6.1(e^— fJlV, 



9 



where Q is expressed in g-cal and calculated for 1 cm of surface per day. 



When using these formulae, the greatest difficulties are encountered in the computation of 

 e g value. Indeed, the wind speed can with certain approximation be determined by means of syn- 

 optic charts. The temperature of the sea surface changes so slowly that in the areas where regular 

 oceanographic observations are conducted it can be forecast rather accurately. However, the e ^ 

 value varies all the time depending on the air masses that move above the sea at the given moment. 



Figure 4. A scheme of fog with wind blowing from ice edge. 



-.^^ 



ICE 



Figure 5. A scheme of fog over the Caspian Sea on 31 May 1939. 



36 



