Nonlinear spectra of shallow water waves

The problem of spectra interpretation of nonlinear shallow water waves is studied in terms of interacting Korteweg-de Vries (KdV) solitons and quasi-linear wavetrains. The method of data processing of random wave field is suggested and illustrated by an example. The soliton component obscured in the random wave field can be determined either on the basis of the inverse scattering method or by direct numerical solution of the KdV equation. The distribution function of number of solitons on amplitudes was constructed for the illustrative example. The relevance of the suggested approach to field measurements is discussed.