Determination of a fast and stable algorithm to evaluate suspended sediment parameters from high resolution acoustic backscatter systems

摘要

High resolution multi-frequency acoustic backscatter systems have significantly advanced the measurement of suspended sediment parameters in the marine environment. Such systems have proved to have important advantages over other techniques when determining the fine-scale variations in the local suspension field, both temporally and spatially. The use of multiple frequencies also enables the variations in radius of the suspended sediments to be determined, due to the differential scattering properties of suspended sediments with frequency. A problem associated with the inversion of the backscattered acoustic pressure to absolute measurements of suspended sediment concentration and particle radius is that for successively higher operating frequencies and increasing concentration the acoustic signal is more rapidly attenuated. When the attenuation is high, standard inversion procedures tend to become unstable and can diverge to zero or infinity. This paper aims to compare the accuracy and stability of two algorithms for determining the concentration of suspended sediments. Comparisons between inversion techniques are conducted, and an assessment of their relative merits is discussed.