SEAWAY 



49 



Darbyshire 



IJeumcnn 



Roll-Fi'scher 



o -o Computed 



+ + 90%Cor.f!dence Bond 



3C 32 IS 12 



T 



Fig. 51 Computed spectrum and its 90 per cent confidence bands compared 

 with theoretical Darbyshire, Roll-Fischer, and Neumann spectra for an 18.7- 

 knot surface (or 28.05-knot gradient) wind (from Neumann and Pierson, 



1957) 



Neumann 



OStd 



25 30 35 40 



Windwirkungsdauer \ 



Fig. 52 Relationship between wind duration and wave height at wind speed of 30 knots. Ordinates are heights of significant 

 waves in meters. Abscissas — wind duration in hours. Walden's data, obtained from ten weather-observation ships are 

 shown by dotted line labeled "atlant. WetterschifFe 1953" (from Walden, 1953/54) 



