Abstract:

A great deal of reverberation data collected and processed for scattering strength is truncated such that angles containing energy from fathometer and hybrid eigenray paths are disregarded. This practice has been a result of the common use of plane-wave direct path scattering models, which inherently cannot compute these events. The recent development of the acoustic scattering model SCARAB (scattering reverberation and backscatter) has provided a tool for investigating the information contained in this low grazing angle scatter. Data taken during the Critical Sea Test (CST) initiative has been processed using traditional direct path methods retaining data at scattering angles well below that where fathometer and hybrid path contamination occur. Model to data comparisons have shown excellent agreement, providing new insight into the dominant mechanisms for scattering from the seabottom. Utilization of the low grazing angle fathometer and hybrid paths is found to be critical in defining the physical control mechanisms of seabottom scatter at all angles. [Work supported by ONR.]