Estimations of the nonlinear properties of the internal wave field off the Israel coast

The measurements of the vertical structure of hydrological fields and internal waves on the Levantine Sea's polygon in the Mediterranean, obtained in the 27-th cruise of the RV "Professor Kolesnikov" in 1991, have been used to estimate the kinematic and nonlinear characteristics of the internal wave field. Statistical and spatial distributions of the vertical profiles of the Brunt-Vaisala frequency are described. They have been used to calculate the coefficients of the Korteweg - de Vries equation. This equation forms the main model for nonlinear parameters. It is shown that the variations of the long wave speed propagation and the dispersion parameter are relatively small in comparison with the variation of the nonlinear parameter. Estimations of the nonlinear properties of the internal waves, being measured, based on the calculation of the local Ursell parameter are given. This method can be used for investigation of the internal wave transformation processes in oceanic regions with horizontal variability of the hydrophysical fields (temperature, salinity) and sloped sea floor.