Factor Analysis of Deep-Sea Acoustic Fields Based on Polynomial Chaos Expansion

Oceanic environmental parameters exhibit random spatial and temporal distributions, leading to significant uncertainty in underwater acoustic fields. Identifying which environmental parameters the sound field is responsive to becomes crucial prior information. This paper proposes using the polynomial chaos expansion method combined with the Sobol' indices to quantitatively assess the impact of environmental parameters on the energy and phase of the deep-sea acoustic field. Using sea trial data, the influence of hydrological and seabed parameters on factors in the near-field deep-sea environment is assessed, with Ray theory offering explanations for Sobol’ indices distribution. The results indicate that the sound speed of the water column from the transmission depth to the reception depth is the most critical environmental factor; the water sound speed above the transmission depth becomes significant; the water sound speed below the reception depth and seabed parameters are less important factors. This study provides a viable factor analysis method for deep-sea environments, offering essential reference information for simulation or experimental setups.