Bottom backscattering in the Java Trench area and the Tasman Sea

Abstract

Acoustic backscattering strengths of the sea floors in the Java Trench, and the Tasman Sea near Sydney, have been measured for the first time. The results obtained for the Java Trench area are, on average, several decibels lower than the Tasman Sea results, which are similar to results that have been published for the bottom of the Atlantic Ocean. In each area, the standard deviations of the station-to-station variability are generally around 5 dB. All of the backscattering strengths increase with frequency; the rate of increase is greater at the lower grazing angles. The backscattering strengths also increase with grazing angle, and the rate of increase is greater at the higher grazing angles. Sea floors at depths from 4 to 7 km have similar backscattering strengths to each other, whereas sea floors at 1 to 2 km depth tend to have lower backscattering strengths.