57 



vertical moisture transport was studied in terms of the so-called "profile 

 coefficient," a number which is proportional to this exchange. As is shown 

 in Figure 11, a distinct increase of this profile coefficient is observed 

 for wind speed about 15 m/sec which is accompanied by a corresponding 

 increase of evaporation. 



m/MC U»„ 



Figure 11. Profile coefficients T of water vapor pressure at U m height 

 as a function of the wind speed ui^ measured at ^4- m. 

 Full circles: Open sea (Brocks, 1959) 



Open circles: Wind-water tunnel (Okuda and'Hayami, 1959)- (from 

 Brocks, 1963) 



Of course, it would be very welcome to get some evidence on the sea 

 spray effect provided also by measurements in the field. Such measurements 

 are of interest not only because of the expected effect of sea spray on the 

 evaporation and vertical moisture transport, but also because it has been 

 suggested that the larger droplets ejected from the sea surface will be 

 accelerated by the wind and thereafter, when falling back into the sea,, may 

 contribute to the downward transport of horizontal momentum, i.e. to the 

 wind stress acting on the sea surface . Relevant measurements have been 

 undertsiken quite recently during the Aruba Expedition of the Woods Hole 

 Oceanographic Institution under the supervision of E. B. Kraus (196I+). A 

 second expedition is now under way. There is some hope that some useful 

 results will be brought out with regard to the almost unknown effect of sea 

 spray . 



After the critical remarks I made with regard to the bulk aerodynamic 

 method some suggestions would perhaps have been appropriate on how the 

 vertical fluxes of sensible and latent heat could be estimated better. 

 Certainly, there are methods that can be applied with considerably higher 

 reliability, but they require a much greater instrumental expenditure. 

 Measuring the fluctuations would be the most direct approach but also 



