THE SPATIAL CORRELATION OF ROUGH SEABED SCATTERING OF SURFACE-GENERATED AMBIENT NOISE

This article considers the effect of rough seabed scattering on the sp atial correlation of low-frequency ambient noise. Extending the study presented by Liu ct al. [J. Acoust. Sec. Am. 93, 753-769 (1993)], it i s shown here that seabed roughness may alter the horizontal spatial co rrelation of the noise field primarily through the excitation of an in terface wave along the bottom. The horizontal coherence and directiona lity of the noise held are shown to be a function of the correlation l ength and angular dependence of the roughness. Since the interface wav e component decays rapidly away from the bottom, the vertical noise fi eld correlation is minimumly affected by the seabed roughness. An exam ination of the noise field under two different statistical description s of seabed roughness, the Goff-Jordan and Gaussian models, shows that detailed differences in the roughness spectral shape produce only min or changes in the noise spatial correlation at infrasonic frequencies.