Abstract:
An experiment to study acoustic backscattering from deep-ocean sediments was conducted in July 1993 as part of the Acoustic Reverberation Special Research Program (ARSRP). An acoustic source transmitting chirp signals in the frequency range 250--650 Hz and a 24-element vertical receiving array attached to the source were suspended near the seafloor over a sediment pond in the vicinity of the Mid-Atlantic Ridge. In a previous paper [Tang et al., J. Acoust. Soc. Am. 98 508--516 (1995)], a study on bottom scattering due to sediment volume inhomogeneities in this area was presented. Here, the spatial and temporal coherence of the scattered field using the data collected on the vertical array will be examined. The scatterers are modeled as point scatterers. It is shown that when the coherently reflected signals due to sediment layering are removed from the measurements, the results of the point scatter coherence model agree satisfactorily with data. [Work supported by ONR.]