Snell's Law:
Total power between wave rays A''A and B''B (wave height 
, group velocity 
)
Total power between wave rays AA' and BB' (wave height 
, group velocity 
)
In the case 1 is at 
then we replace subscript 1 with 0 and put no subscript for 2 (at depth d)
Then H at depth d is related with 
at infinite depth from:
Textbook(SPM) defines as
= wave height in deep water if the wave is not refracted
is given as 
on Table C-1 of the 2nd volume of SPM.
Then the refraction coefficient may be defined as:
From geometry shown in figure at the beginning of this section.
(remember 1 
0, 2 no subscript)
