this assumption is not fulfilled too well. Thus some numerical 
results of wave refraction theory must not be taken too quanti- 
tatively although they may be correct within 30 or 40 per cent. 
Were the theory derived rigorously, it might then be possible to 
estimate the amount of error introduced by the above assumption in 
a practical case. 
ae a a a  - 
From the results of the past chapters, it is possible to deter- 
mine the two dimensional power spectrum at a point located offshore 
in deep water from a point of interest in the refraction zone. For 
example, the power spectrum could be determined by direct measure- 
ment from stereo-aerial photographs and deep water wave records as 
a function of time at a point a few miles from the coast under in- 
vestigation. By the methods of Chapter 9, if the torm power spect- 
rum were known, it would then be possible to forecast the power 
spectrum offshore from the point of interest. Given these deep 
water quantities, what can be said about the records which can be 
obtained in the transition zone? 
The problem can be solved to various degrees of accuracy. 
Given a linear sloping beach, and the results obtained by Peters* 
expressed in terms of the parameters, # and 9, and a deep water 
wave of unit height, then it would be possible to find a represent- 
ation for the sea surface in the transition zone by a Lebesgue 
Power Integral in the Gaussian case over the power spectrum multi- 
plied by Peters' solution. At any point the wave record as a function 
of time would be Gaussian. As a function of x and y, the elemental 
Feces ences to Part I. The paper has appeared in the publication 
ed. 
32 
