Acoustic sensor performance in coastal waters: solid suspensions and bubbles

Coastal waters may be characterised by depth-dependent populations of suspended solid particles and microbubbles. These populations may be acoustically significant in that they may modify the complex wavenumber for compression waves, increasing the volume attenuation and altering the phase speed. These effects have been incorporated into a ray-based sonar model and results are presented which show that they may have a significant effect on the performance of high frequency acoustic sensors in coastal waters. The application of this work to acoustical oceanography is illustrated by means of a speculative proposal to use trans-estuarine transmission measurements to monitor suspended sediment load.