Computation of Horizontal Correlation of Sound in Presence of Internal   Waves in Deep Water and Long Distances
  Numerical solutions are given for a parabolic approximation of the acoustic wave equation at 200 and 250 Hz in two and three spatial dimensions to determine if azimuthal coupling in the cross-range coordinate significantly affects horizontal correlation in the presence of internal gravity waves in the sea. No evidence for coupling is found for distances of 4000 km and less. This implies that accurate solutions are possible using computations from uncoupled vertical slices. Shapes of horizontal correlation are closer to shapes given by two theories than at lower frequencies. 
John L. Spiesberger
physics.ao-ph