Ochi-Hubble Spectrum
The Ochi-Hubble spectrum (Ochi and Hubble 1976) is a six-parameter
spectrum proposed for bimodal sea states consisting of swell and local wind-
generated components. It can be written as:
γ1
4γ +1 f -4
(4γ1 +1)(2πf p1)4 / 4
π
H 2 exp - 1
S( f ) =
4 f p1
4γ1+1
s1
Γ(γ1) (2πf )
2
(B11)
γ2
4γ +1 f -4
(4γ2 +1)(2πf p2 )4 / 4
π
H 2 exp - 2
+
f 2
4γ2 +1
s2
Γ(γ2 ) (2πf )
2
4 p
where Γ is the gamma function. Hs, fp, and γ denote the significant wave height,
spectral peak frequency, and spectral shape factor respectively for the two sea
state components. When γ is equal to 1, the Ochi-Hubble spectrum reduces to the
Bretschneider spectrum.
B4
Appendix B Description of Ocean Wave Spectra
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