Broadband acoustic wave propagation and scattering in Delaware Bay Estuary

Abstract

Physical oceanography of estuaries is complex due to many factors including fresh water river discharge, oceanic salt water intrusion, variable ebb and flood tides, and surface winds. In these confined environments, high frequency (1–25 kHz) broadband acoustic waves are shown to through large intensity fluctuations with substantial energy scattering due to their interaction with the sea surface, sea bottom, and refraction due to the stratified water column. In this paper, we present results from a series of experiments that were conducted in the Delaware Bay estuary where fixed source-receiver configurations allowed calibrated long-term acoustic and oceanographic measurements to be conducted while atmospheric conditions such as wind speed and direction were carefully measured concurrently. It is shown that intensity fading due to oceanographic features and tide induced sound speed profile refraction in stratified water column occurs regularly and periodically. Wind generated surface gravity water waves in...