Exact distributions for apparent waves in irregular seas
Krysztof Podgórski, Igor Rychlik and Ulla E.B. Machado
Department of Mathematical Statistics,
Lund Institute of Technology,
We discuss the long-run distributions of several characteristics for
the apparent 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 instantaneous profile along a horizontal line; 3) the encountered seaway.
Exact integral forms of the joint long run distributions are
derived for the apparent periods, lengths, and heights. Results of numerical
approximations of these distributions are presented in examples. For the
computations we considered, as the input spectra, empirical estimates of
the frequency spectra as well as JONSWAP type spectra. Effective algorithms
are discussed and utilized in the form of a comprehensive computer package
of numerical routines.