In order to have a firm basis for the prediction of reverberation or back-scattering of sound in the sea, field measurements leading to values for a back-scattering coefficient of the sea surface and bottom have been made. Variation of this coefficient with angle of incidence of the sound beam provides some interesting clues as to the back-scattering processes which operate....
Urick, R. J.. 1956. "The processes of sound scattering at the ocean surface and bottom." Journal of Marine Research 15, (2). https://elischolar.library.yale.edu/journal_of_marine_research/869