Mid-frequency geoacoustic inversion of source tow data from the ASIAEX east china sea experiment

During the 2001 ASIAEX East China Sea experiment, source tow data were collected by a 16-element, 75-m aperture vertical line array in 105 m deep water. Continuous wave tonals at 95, 195, 295, 395, 805, 850, and 905 Hz were transmitted from a J-15 transducer at a nominal depth of 47 m. An environmental model in the study area initially was derived by matched-field geoacoustic inversion using the low frequency data (195, 295, and 395 Hz). The quality of the inversion was checked by source localization over an interval of time while the source range varied from 1 to 3.5 km. In this study, the mid-frequency data (805, 850, and 905 Hz) are incorporated into the inversion procedure. The results indicate that the bestfit model found using the lower frequency band can be extended one-octave higher in the application of MFP source localization despite higher sidelobe levels. The quality of the refined model again is confirmed by time-continuous, source localization using the higher frequency data over the same time interval.