Determination of parameters of low-frequency internal waves in the coastal zone of a fringing sea using field measurements and basing on the nonlinear theory

A method is presented to determine the quadratic nonlinearity parameter and amplitude of low-frequency internal gravity waves in the coastal zone of a fringing sea, based upon their propagation rate dependence on local value of pycnocline vertical displacement produced by the waves. To test the method, the internal wave field observations in the coastal zone of the Sea of Japan are used. The testing results show that the internal wave parameters calculated using the proposed method and the experimental data are in a good agreement with those calculated from theoretical formulas.