Seafloor Roughness

Abstract

Seafloor roughness can be a dominant contributor to sound scattering at higher acoustic frequencies, causing reverberation through backscattering and altering propagation through forward scattering. Seafloor roughness, especially that associated with sand ripples, can also diffract sound downward into the sediment promoting the seafloor penetration necessary for sonar detection of buried objects. Together with sediment sound speed, attenuation, and bulk density, a statistical characterization of seafloor roughness, often in the form of RMS roughness, RMS slope, or power spectral density, is a critical input to most scattering and penetration models described in Chs. 13 and 15. Much of the present body of knowledge, especially related to measurement techniques and statistical characterization, comes from studies in geology, geophysics, and oceanography, but an increasing effort is being directed toward specific high-frequency acoustic applications. This recent work is the primary subject of this chapter.