the leeward fetch edge. 



(li) Energy was being transmitted to the entire frequency range of the spectrum 

 simultaneously. 



(iii) A particular spectral component, of frequency somewhat higher than the 

 wind frequency, grows until it has occupied the position of the spectral peak. 

 After that time (distance) the component does not maintain its maximum energy, but 

 instead, loses energy until it reaches a final equilibrium value which is between 

 30-70% of the maximum. This indicates that a simple power law description of the 

 wave breaking region (generally called the equilibrium range) may not be adequate. 

 A more complicated relation, such as (14), suggesting a connection between wave 

 breaking and the position of the spectral peak seems called for. 



(iv) The observed rates of spectra! growth are in substantial agreement with the 

 observations of Snyder and Cox (1966). This agreement lends considerable support 

 to the conclusions drawn by those authors concerning the wind generation of ocean 

 waves . 



(v) The predictions of Phillips' (1957) theory concerning wave generation by 

 turbulent otmospheric pressure fluctuations are in good accord with the observed 

 growth rates. The data suggest, however, that under unstable atmospheric conditions, 

 the pressure spectrum scaling factor (Priestley, 1965) must be increased by several 

 orders of magnitude over that expected for near-neutral conditions in order to make 

 the theory compatible. 



(vi) The predictions of Miles' (1957) theory concernung wave growth by an 

 instability mechanism are not in agreement with present data. This reaffirms the 

 conclusion of Snyder and Cox, that the instability which is present appears to be 

 an order of magnitude stronger than predicted by Miles. It is interesting, and per- 

 haps suggestive, that the "simple" empirical relation, (15), proposed by those 

 authors is in good agreement with the downwind data. 



(vii) It is of considerable significance that the coefficient of exponential growth, 

 )S (Figure 16), is positive for waves whose phase speeds are equal to or greater than 

 the v/ind speed. 



(viii) Estimates of the fetch distance where a component occupies the steep 

 forward face of the spectrum are in good agreement with other data. The observa- 

 tions also indicate that these fetch distances are 2 to 4 times greater than the 

 transition distance as defined by Phillips and Katz (1961). 



50 



