214 



Condensation (downward flux of heat) 



(3) Sensible heat transfer 



Conduction toward or away from the surface in the thin laminar layer 

 (if such exists, on the air side of the sea surface) and convection in the 

 turbulent air above. (Some sensible transfer is effected also by spray, 

 salt flux, precipitation, solution of gases from the air, etc.) 



(4) Kinetic energy transfer 



Associated with momentum transfer from air to sea. 



In addition to the transfer of energy, the transfer of mass across the sea 

 surface is important. The transfer of moisture, inseparably associated with the 

 transfer of latent heat, is important in its own right. In addition, the transfer 

 of salt particles to the air is important to the moisture cycle of the atmosphere, 

 as Woodcock and others have shown. The upward flux of salt within the water 

 would perhaps help> shed some light on this problem. Finally, absorption of 

 gases at the sea surface, especially oxygen, is of significance to the life cycle of 

 the sea. 



METHODS OF MEASUREMENT 



The direct flux of sensible heat, vapor, and momentum by turbulent 

 processes can be shown to be given by the following formulas: 



(1) Flux of sensible heat = Dc^ w'x^', 



(2) Flux of moisture - f-^ w' q' , 



(3) Flux of x-directed = f^ w' u', 

 momentum (shear 



stress in the x- 

 direction) 



(4) Flux of salt = f^ w' s' , 



where r is the density of the fluid, Cy is the specific heat at constant volume of 

 the fluid (air or water, depending upon which medium is investigated with respect 

 to the flux of heat), u' is the eddy component of horizontal velocity in the x-direc- 

 tion or anomaly of velocity from the mean value u over a time interval T, w' is 

 the anomaly of vertical velocity from the mean value w over the time interval 

 T,!^' is the anomaly of temperature, q' is the anomaly of specific humidity, 

 and s' is the anomaly of salinity of the water. The bar over the top of the vari- 

 ous products indicates an average for the time interval T, i.e. 



u'w' 



r. t -I- T/2 



] u'w' dt. 



T/2 

 where 

 and 



Each pair of quantities!^' and w', q', and w', u' and w' must be observed 

 simultaneously at a given point and must represent anomalies from means evalu- 

 ated for a common time interval in order that accurate values of flux are ob- 

 tained from their mean products. The time interval T which is chosen as the 

 averaging interval for^T", q, u, and w, as well as for the products!^ 'w'. 



