Estimation of Sound Speed Profile from MODAS and Its Effect on Sound Propagation in the South China Sea

Satellite remotely-sensing observations are used to reconstruct the underwater environment of temperature and salinity which was named as the method Modular Ocean Data Assimilation System (MODAS) by US navy laboratory. The MODAS in the South China Sea has been developed by the South China Sea Institute of Oceanology, Chinese Academy of Sciences. Based on the system, this paper estimates the sound speed profile from MODAS and Argo and its effect on sound propagation in the South China Sea. Although the overall root mean square error (RMSE) was only 1.3m/s, the error was mainly within 200m, reaching 4.8m/s maximally. The inversion error of sound speed profile did not affect the location and width of convergence zones in deep-sea channels, but the surface duct was abnormal.