Estimation of sound speed profile based on optimal spatial correlation radius: A case study of the Northwest Pacific

As one of the significant factors in determining the propagation mode of the underwater acoustic signal, the accurate acquisition of the sound speed profile (SSP) is crucial for constructing underwater acoustic systems. Ocean observation data are sparse on a horizontal scale, making the accurate estimation of the SSP based on available data become a research hotspot in oceanography and hydroacoustics. In this paper, we propose the concept of spatial correlation radius (SCR) of the SSP sets for the first time and achieve an accurate estimation of the SSP based on the optimal spatial correlation radius (O-SCR). Taking the Northwest Pacific as an example, the Argo float profile data of multiyear are employed to build a database of the O-SCR and conduct validation. The results show that the proposed strategy can effectively estimate the SSPs with a mean absolute error of less than 2.5 m/s. An eddy is identified via our frame, and the estimated core depth differs from the true depth by 6.7%. The acoustic transmission loss (TL) results illustrate that the proposed method can achieve more accurate acoustic field prediction in a distance-dependent environment. The estimation of the SSP based on the O-SCR provides a dependable technique for the precise perception of ocean sound speed field-acoustic field environment.