Steepness and spectrum of nonlinear deformed wave in shallow water
  Process of the nonlinear deformation of the surface wave in shallow water is studied. Main attention is paid to the relation between the Fourier-spectrum and wave steepness. It is shown that the spectral harmonics of the initially sine wave can be expressed through the wave steepness, and this is important for applications. 
Irina Didenkulova, Narcisse Zahibo, Andrey Kurkin, and Efim Pelinovsky