Exact distributions for apparent waves in irregular seas

We discuss the long-run distributions of several characteristics for the ap parent waves in a Gaussian sea. Three types of one-dimensional wave records are considered: 1) the: seaway in time at a fixed position; 2) the instant aneous profile along a horizontal line; 3) the encountered seaway. Exact in tegral forms of the joint long nln distributions are derived for the appare nt ent periods, lengths, and heights. Results of numerical approximations o f these distributions an presented in examples. For the computations we con sidered, as the input spectra, empirical estimates of the frequency spectra as well as JONSWAP type spectra. Effective algorithms are discussed and ut ilized in the form of a comprehensive computer package of numerical routine s. (C) 2000 Elsevier Science Ltd. All rights reserved.