Title: Geoacoustic inversion for bottom parameters in a thermocline environment in the northern area of the South China Sea

Author(s): LI Mengzhu; LI Zhenglin; Li Qianqian;

Affiliation(s): State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences; University of Chinese Academy of Sciences; College of Geomatics, Shandong University of Science and Technology;

Abstract: Bottom acoustic parameters have important influence on the application of underwater acoustic propagation and source location. The acoustic parameters of the seabed in the northern of the South China Sea (SCS) were inversed using the experiment data from an acoustic experiment in 2015.Based on the comprehensive analysis of the influence of the sound speed fluctuation and the geoacoustic model on seabed inversion, the multi-parameter hybrid acoustic inversion scheme is improved by selecting the equivalent mean sound speed profile (SSP) and half-infinite liquid bottom model to save the inversion dimensions in the matched field processing (MFP) inversion. The inverted bottom sound speed and density are in good agreement with the core sampling measurements. The nonlinear empirical relationship of the attenuation coefficient with frequency is given out. The inversion results are meaningful to the sound propagation research and application in the northern area of the SCS.