44. The Phase III methodology assumes that, at the Phase II station, 



E^(f) can be represented parametrically using only two parameters: the 



energy based significant wave height f-L and the frequency of the spec- 



ra Q 



tral peak f m . This one-dimensional spectrum is then given a directional 

 distribution using the following equation: 



E 2 (f,e) = E^f) |^ cos 4 (8 - e m ) (2) 



Here, 6 is the central angle of the spectrum. E_(f,9) is discretized so 

 that each component can be propagated from the Phase II station to the 

 Phase III station in accordance with linear wave theory. 



45. The Phase III methodology assumes straight and parallel bottom 

 contours so that refraction and shoaling of swell and of the discrete ele- 

 ments of E„(f,9) may be determined analytically. The sea is further trans- 

 formed by wave-wave interactions. Depth-controlled criteria limit both H 

 and Hjjj . Sheltering by capes or peninsulas is included in the Phase III 

 methodology. 



46. Refraction, shoaling, and depth limitation acting on the swell 

 transform H , f , and 9 at the Phase II station into new values in shallow 

 water at the Phase III station. If the Phase III station were sheltered from 

 the swell, then H is zero. Refraction, shoaling, wave-wave interactions, 

 and sheltering acting on individual components of the sea result in a new 

 spectrum for sea at the Phase III station. PL , f , and 9 are extracted 

 from this spectrum. 



47. The final Phase III result comprises six wave characteristics: H , 

 f , and 9 of the swell and [^ , f m , and 9 of the sea. The wave 

 climate at the Phase III station is taken to be completely defined by these 

 six parameters. 



Use of Phase III Methodology for Broad Sound Wave Climate Simulations 



48. WIS Phase II, sta 13, directional spectra were used as deepwater 

 input. This station is located at latitude 42° 32.5' N and longitude 70° 14* 

 W. The Phase III station was positioned at latitude 42° 23.5' N and longitude 



41 



