o~~~~~~~~~~~

Fig. 3.4 Ray path projections on the (a) xz and (b) yz planes in an atmosphere with exponential profiles of V.l (z) and Vr (z) [50 J. The numbers beside the curves indicate the value (in degrees) of the angle rp between the sound rays near the source and the z-axis.

upwind there is antiwaveguide sound propagation causing an acoustical shadow zone at certain ranges from the source.