Empirical studies of two kinds have "been conducted which could shed 

 some light on the problems of the functional form of the transfer relation 

 and the values of the transfer coefficients. However, these studies have 

 not been carried far enough to solve the general problem, and the data from 

 these studies have generally been used only to provide limited and immediate 

 practical answers for some special needs. 



The one general result which does appear to emerge from these studies is 

 that we can assume zero sensible heat transfer in the stable case, i.e. where 

 warm air passes over cold water, and probably zero latent heat transfer as 

 well, as far as large scale dynamical effects are concerned . Obviously, the 

 well-known modifications of the shallow surface layer are important for 

 weather prediction; poleward moving surface air cools, and fog and stratus 

 do form. But while these results must be included in the complete weather 

 prediction computation, the total energy transfer involved is small, the 

 effect does not penetrate very high, and its dynamical consequences are 

 probably negligible . 



The data from Burke's ( 19^+5 ) early experiment — carried out at 

 Sverdrup's suggestion -- are unfortunately not presented in a form that 

 permits one to relate the sea-air energy transfer parametrically to macro- 

 scale variables. Craddock's (1951) data are somewhat more useful in this 

 regard. Several years ago (Spar, 19^2) I tried to use the Lagrangian 

 trajectory technique, as Burke and Carddock had done earlier in their studies 

 of air mass modification, to evaluate the transfer coefficients for sensible 

 heat and water vapor. The results, based on 238 12-hour trajectories off the 

 east coast of the United States were the following; 



In the case of "effective heat fliix," (i.e. the sensible heat flux plus 

 radiative heating plus that latent heat released locally in the cold air by 

 cumulus formation and showers) the formula 



H = 10 Vq (T^ . Tq) (1) 



(H in ly day , V the average "surface" wind along the 12-hour trajectory 

 in m sec " , Tg ana T_ the average sea surface and "surface" air temperatures 

 in degree C) gave "satisfactory" results in the sense that the correlation 

 between the left and right hand sides of the formula was about 0.6. 



The transfer coefficient above may be compared (although the comparison 

 is not strictly valid) with some others (see Table I). 



Table 1. Sensible (and effective) heat transfer coefficients, 

 Ks7 from various sources. 



Dimensions: ly day" (m sec" )" degree ~ C. 



