anos 
Wind force, Beaufort 1 a 3 pA I ema ae 6 
e, em mb-1 day-1 0.012 0,023 0.041 0.072 0.122 0.190 
(In estimating these values for ec the evavoration from spray has been 
included along with the evanoration fro: the sea surface itself.) 
Due to the latent heat withdrawn in vanorization, for every 
centimeter of water evaporated about 590 cal em7¢ of heat is utilized, 
ee that water is cooled by evavoration at the rate 
He = Ne (eg - e)e 
The factor he has the values: 
Wind force, Beaufort 1 2 3 4 > 6 
Ne, cal mb-1 em=@ day~1 SNARE el AAR ROS SCE ah a ea 
Evaporation not only cools the surface water but also increases 
its salinity, both of which increase its density. Except at low tem= 
peratures the density is more affected by the cooling than by the 
increase of salt concentration. Since the other factors producing 
a change in density all involve heat it is convenient to replace 
this salinity increase by an equivalent heat loss. Thus the effect 
on density of the salinity increase may be revresented by a fic- 
titious heat loss 
He Sik Hats 
where k has the values (for salinity 35 per mille}: 
Water temperature, °F 30 «. 40 -.50 60 70 80 90 
k 146 0,44 (O,29 Ove . 0,18) 0.15) 0ens 
As far as density is concerned, evaporation leads to a total effective 
heat loss 
Het Ha = He (D+ be 
ee ee 
Let S be the rate at which solar radiation is absorbed by the 
