3^^ 



With a view to this severe handicap it is only of little comfort that, 

 on the other hand, the sea surface also has a few pleasant properties. The 

 local differences, which are most prominent over land, are substantially 

 reduced on the oceans, these being much more uniform in this respect than 

 the continents are. Their capability of acting as sources or sinks for 

 heat and moisture shows but little variation from one place to another. 

 For example, it has been recently reported by Brocks (1963) that, in the 

 southern part of the North Sea, the correlation between simultaneous 

 measurements of air temperature as well as between that of humidity or wind 

 speed executed within a sea area of at least 25 nautical miles was found 

 to range mostly between O.9 and 1.0, which proves the high degree of spatial 

 homogeneity at least for this area. Further, since the diurnal and annual 

 variations are much smaller than those on land, there is also a pronounced 

 uniformity in time at sea. Thus, in some respect, the oceans offer an 

 ideal field for meteorological investigation provided that it is possible 

 to overcome the experimental and theoretical difficulties mentioned before . 



Every review must have a certain reference level from where it starts, 

 i.e. a certain amount of knowledge which can be taken for granted, since 

 it is impossible to give a complete treatment within a rather short time. 

 Such a reference level can best be provided by a suitable publication. 

 I am in the happy position of being able to make reference to two excellent 

 reviews on our present subject. The first, given by E. L. Deacon and E. K. 

 Webb (1962) provides a very concise and still detailed treatment of small- 

 scale interactions air-sea. The viewpoint of the second review, which has 

 been elaborated by 8 distinguished scientists (Benton et al., I962) is more 

 general, its main object obviously being to put the finger in the wound of 

 insufficient knowledge and to show what should be done about it. 



I shall take these two publications as a base for my discussion assuming 

 that the state of affairs as it is reported therein is more or less known 

 to the audience . 



The interchange occurring in the boundary layer air-sea is manifold. 

 When attempting to treat it systematically we may perhaps make a subdivi- 

 sion by separating 



the exchange of energy from 



the exchange of matter and from 



the exchange of electrical charge . 



Although the transfer of matter and of electrical charge through the 

 boundary layer certainly has interesting or even fascinating aspects, I 

 would rather like to confine my discussion to the exchange of energy thereby 

 including the exchange of water which, owing to the latent heat of vaporiza- 

 tion, must be considered as a - quite important - part of the energy transfer. 



