Geoacoustic inversion using SA in East China Sea experiment

Information of geoacoustic properties is very important to predict sound propagation in shallow water, but in general, it is difficult to measure directly. An experiment for studying those properties acoustically was conducted in the shallow water of the East China Sea. In the experiment, a continuous wave with a source level of 180 dB to 185 dB was sent out by a hydraulic-type projector, which was towed with a constant speed at fixed depth over 30 km. The propagating sound was measured using a moored vertical line array composed of 8 sensors. As a method for estimating the geoacoustic properties, matched-field processing (MFP) combined with simulated annealing (SA) was employed. Correlation between the measured and calculated pressure fields was totally taken over around 100 points in the water column. These locations can be demonstrated to affect efficiency and speed in SA.