Inversion of ocean sound speed profiles from travel time measurements using a ray-gradient-enhanced surrogate model

Abstract

ABSTRACT Sound Speed Profiles (SSPs) are critical environmental parameters for many ocean applications. A novel Ray-Gradient-Enhanced Surrogate Model (RGE-SM) method is proposed for SSP inversion by matching the predicted acoustic travel times with the measured acoustic travel times. The surrogate model is adopted as the framework to search for the global solution of SSP parameters. Instead of approximating the objective function, the proposed method constructs the surrogate of the objective function’s lower envelope by finding local minima based on the ray gradient of the objective function. The RGE-SM method is verified using SSP data in the South China Sea, and the results show that the RGE-SM method exhibits a smaller estimation error than the genetic algorithm with less than one-twentieth of the calculation time.