details of the spectral equilibrium in the range of high 

 wavenumbers responsible for microwave backscattering still 

 remain to be clarified before microwave techniques can 

 become a reliable tool for the measurement of sea state or 

 the determination of mean sea level to the decimeter accura- 

 cies needed for oceanographic applications. 



1. INTRODUCTION 



Miles' (1957) and Phillips' (1957) important work on 

 wind-wave generation marked the beginning of a fruitful 

 period of theoretical research in ocean wave dynamics. A 

 number of alternative mechanisms of wave growth have since 

 been proposed (e.g. [l4] [15] [19] [21] [22] [28] [29] [^^] 

 [50]), many of which take more detailed account of the 

 turbulent response characteristics of the atmospheric bound- 

 ary layer than these first theories. Further theoretical 

 investigations have been concerned with the effects of wave- 

 wave scattering ([20a, b,c] [42] [54] [56]), interactions of 

 waves with currents ([26] [31] [32] [33]), the coupling 

 between short waves and long waves ([24] [29] [43]), white 

 capping ([29] [4]), and other processes. A general summary 

 of most of this work can be found in Phillips' (I966) compre- 

 hensive monograph; a more specialised presentation from the 

 viewpoint of weak interaction theory is given in Hasselmann 

 (1968). 



25-3 



