5h 



After inserting the empirical functions f-j^, f^, ^^ into our initial equations 

 (5) for the fluxes of sensible and latent heat we obtain 



c p C f ^ (A0" , u ) u 2 

 H = P a 2 a* a a 



E 



P ^a ^3 ^^^a' "a' ''V V 



(9) 



These relations are considerably more complicated than the bulk aerodynamic 

 formulae normally used and render themselves not so easily to practical 

 application as the original relations do. They clearly show however the 

 deficiencies inherent in the usual bulk aerodynamic approach. Even ±f we 

 presume as a first approximation that the f-functions are linear in their 

 main variable, we would not get rather much farther. Then we would have the 

 following equations 



" = ^p P ^a ^'o - «a> "a ^ <^» ^V 



E = p C^ (q^ - q^) u^ f^ (u^, Ae^) 



(10) 



which contain two other empirical functions and decisively differ from the 

 original ones and from each other regarding their dependence on u^^ and 



AS . 



a 



Thus the bulk aerodynamic approach does no longer look as simple and 

 as adequate for practical use as before . In order to get a quick check, 

 let us assume that Brocks' graphs may be generally used and that further it 

 is sufficient to approach each of them by one linear relationship in each 

 case thus disregarding the other influences . Even with such a simplification 

 we would obtain rather different coefficients for H and E, namely 



H = 0.58H c p C (e" - F ) u 

 p a o a a 



(11) 



0.8U1 p C (q - q ) u 

 a ^o ^a a 



This example shall only show what difficulties are implied, when using the 

 simple bulk aerodynamic formulae . Certainly, the differences mentioned 



