Inversion of range-dependent geoacoustic properties in South China Sea ASIAEx01 experimental site

• Published in: The Journal of the Acoustical Society of America 2003-04, Vol.113 (4_Supplement), p.2218-2218
• Main Authors: Turgut, Altan, Pasewark, Bruce, Orr, Marshall, Lynch, James, Chiu, Ching Sang
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4780267

Matched-field inversion of range-dependent geoacoustic properties is studied using broadband (50–200 Hz, 240–260 Hz, and 550–600 Hz) acoustic data collected in the South China Sea during the ASIAEx01 experiment. Range-dependent sediment sound-speed and attenuation profiles are inverted using a global optimization scheme based on genetic algorithms to minimize an objective function defined by the Bartlett processor output. For the forward model, an efficient coupled normal mode model is used to calculate broadband acoustic fields incorporating range-dependent bathymetry and sediment layers thickness obtained by chirp sonar surveys. Inversions were performed starting from a range-independent region with a relatively short source/receiver distance. Additional geoacoustic profiles were inverted by incorporating the previously inverted profiles as the source/receiver distance was increased. The results obtained at three different frequency bands are in good agreement, especially when the range-dependency of bathymetry and sediment layers thickness is included in the inversion. [Work supported by ONR.]