It Is necessary to consider first the total amount of 

 heat that reaches a unit area of the sea surface in a given time 

 and is thus available to the water coliomn for absorption at 

 various depths. Mosby (1936) has shown that, with clear skies, 

 the total Incoming radiation may be accurately approximated 

 by the simple linear equation 



Qo=ka (1) 



Here Qo is the total incoming radiation expressed in g.cal. 

 cmr^ min." • k may be considered as a parameter whose value 

 varies with the water vapor in the atmosphere, but its variation 

 is in such a narrow range that, for the purposes of this study, 

 it may be considered as a constant and equal to 0.025. 5 is the 

 mean solar altitude, in degrees, during the period over Xirhlch the 

 heat is calculated. 



This expression must be modified for cloudiness. This 

 problem has been treated empirically by Angstrom (1922) and 

 Kimball (1928). Their findings indicate that the values for 

 the ration of overcast sky radiation to clear sky radiation 

 vary between 0.22 and O.3O, the most likely mean value being 

 0.29. Applying this ratio, we have 



Q^=.025a[0.29+0.7l(l-j^)] (2) 



