than one major wave system about two-thirds of the time (Thompson 1980). Wave climate can vary greatly

between seasons of the year, but variations between years are usually small. At least three full years of data

are desirable for a stable estimate of wave climate. Figure II-8-15 is a typical table of wave climate

information (from one directional sector) from the Wave Information Studies.

(b) The mean *H*s and distribution of *H*s are always of interest in describing wave climate. Both Weibull

and log-normal distribution functions have been used to represent the distribution of *H*s. However, the actual

data usually provide a sufficiently stable estimate and the formal distribution functions are unnecessary.

Means and distributions of *T*p and *θ*p are vital for some applications. Joint occurrence probabilities of *H*s, *T*p,

and *θ*p give a fairly complete representation of wave climate, which is needed in applications such as

nonlinear refraction modeling. When these standard statistical summaries are formed, information about the

simultaneous occurrence of more than one wave system is lost.

Hydrodynamic Analysis and Design Conditions

II-8-29

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