Side‐Scattering of Sound in Shallow Water

When a sound beam travels through the sea, it is scattered in all directions by inhomegeneities of various sorts in the sea and on its boundaries. In the backward direction, the aggregate of all the scattered contributions is called “reverberation.” In other directions, the “side scattering” can be studied by using two directional transducers, trained so that the beams cross each other, to measure the sound scattered out of one beam and received on the other. This method was employed in an off‐shore area in the Gulf of Mexico having a particularly uniform bottom. Using two bottomed transducers a mile and a half apart, the intensity of scattering was measured at 22 kc for different angular orientations of the two beams. The measurements were reduced to the coefficient, scattering strength, without requiring either transducer calibrations or direct measurements of transmission loss.The results indicate a bottom scattering strength between −30 and −40 db having no appreciable dependence on angle between the ...