Accession Number : ADA019159

Title :   Ocean Bottom Reflectivity (A Point of View).

Descriptive Note : Technical document,

Corporate Author : NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CONN NEW LONDON LAB

Personal Author(s) : Santaniello,Salvatore R. ; DiNapoli,Frederick R.

Report Date : 20 NOV 1975

Pagination or Media Count : 16

Abstract : The analysis procedures for extracting bottom loss values from pulsed-acoustic signals that have interacted only with the ocean bottom do not inherently consider sub-bottom refraction and reflection of sound, which are important effects at low frequencies (i.e., <500 Hz). Sound returning from the sub-bottom can constructively interact with sound reflected from the water-sediment interface, yielding 'negative bottom loss' results. To support this premise a Fast Field Program (FFP) time domain model simulation of a bottom loss measurement was performed in which the lateral wave was the only additional arrival interacting with the bottom-reflected wave arrival. The simulation demonstrated a plausible cause for negative bottom loss results and demonstrates that propagation models must accommodate the environmental description of both the water column and ocean bottom.

Descriptors :   *Underwater sound, *Ocean bottom, *Acoustic reflection, Acoustic refraction, Acoustic velocity, Acoustic attenuation, Sediments, Mathematical models, Reflectivity

Subject Categories : Acoustic Detection and Detectors
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE