Influence of oceanic irregularities on the temporal and angular structure of the sound field at the beginning of the far convergence zone investigated by modified ray method

The high frequency asymptotic method of sound pressure calculation at the beginning of convergence zones and at the end of shadow zones is described. The authors find a family of rays that transfer acoustic energy from the source to the receiver without actually joining them. The influence of such rays will be significant in the shadow zone at the beginning of the convergence zone. It starts nearer to the source, and it does not begin with a peak, but gradually. To investigate the influence of the emanating area of the internal tidal waves on the sound field structure, a program calculating the disturbance of the sound speed field in a range-dependent ocean and bathymetry was developed. The results of numerical investigation of the influence of intrathermocline lenses and semi-diurnal tidal waves on the sound field structure within the first kilometers of the convergence zone are observed