Steepness and spectrum of nonlinear deformed shallow water wave
  Process of the nonlinear deformation of the shallow water wave in a basin of constant depth is studied. The characteristics of the first breaking are analyzed in details. The Fourier spectrum and steepness of the nonlinear wave is calculated. It is shown that spectral amplitudes can be expressed through the wave front steepness, and this can be used for practical estimations. 
Narcisse Zahibo, Irina Didenkulova, Andrey Kurkin and Efim Pelinovsky