58 



profile measurements (at three levels) would furnish acceptable values. 

 Finally, if these two possibilities cannot be used, some help can be 

 expected from those 'profile coefficients" which enter the refined bulk 

 aerodynamic equations and which can be obtained from some general tabulations 

 if wind speed and stability are known. It is, however, not possible here 

 to give more details on these procedures . 



CONCLUDING REMARKS 



If some final conclusion shall be drawn after reviewing the present 

 state of our knowledge on the physical exchange processes occurring at the 

 sea surface, then it should perhaps be concerned with the question whether 

 the relationships available at present for computing the vertical fluxes of 

 momentum, heat, and moisture passing through the boundary layer air-sea 

 might be serviceable and reliable enough for calculating these fluxes for 

 large sea areas on a routine basis so that synoptic charts of air-sea 

 exchange can be drawn in order to supply the necessary data for diverse 

 meteorological and oceanographic forecasting purposes. 



The bulk aerodynamic equations certainly are easy to apply, and their 

 application can be based on such data as are normally available from the sea 

 at present. But it seems questionable whether they equally give what we 

 would like to have with sufficient precision. They appear to supply reliable 

 results if the coefficients inherent can be determined separately for each 

 quantity and also for each situation. However, I have some doubt whether 

 this may be possible if a general and permanent application has to be made 

 for a large sea area. Thus, the bulk aerodynamic formulae can only be 

 considered as a very preliminary and incomplete procedure for application 

 on a synoptic scale. 



Therefore, we must look for other sources of information on the 

 turbulent vertical transfer quantities-. The direct measurement by applying 

 the eddy correlation method certainly is not majiageable generally because of 

 the complicated instrumental expenditure needed. However, the profile method 

 should be applicable in a general way. It would necessitate measurements of 

 wind speed, air temperature and humidity each carried out at three levels, 

 but it would be much better if their average vertical gradients at one 

 level (say 5 ni) could be directly recorded with sufficient accuracy. This 

 object, of course, implies a considerable amount of development in instrumen- 

 tation and engineering but, in principle, it should be possible. Using such 

 devices we would get rid of all the problems connected with the drag co- 

 efficient and with the replacing of vertical gradients by differences air- 

 sea. 



Sometimes I -^8» dream^g of air-sea interaction buoys distributed over 

 the oceans in a fairly dense network and broadcasting regularly their 

 measured data on the mean vertical gradients which would enable us to draw 

 reliable charts on air-sea interchange. Let us hope that this dream will 

 not always remain a dream but will become true in* not too distant <^k. future. 



