The Analysis of Acoustic Propagation Characteristic Affected by Mesoscale Cold-Core Vortex Based on the UMPE Model

Abstract

The ocean mesoscale vortex can make uneven distribution of sound energy, which has a significant impact on underwater acoustic equipment, weapons and submarine warfare. Based on the observed data of 2014 West Pacific sea oceanographic survey, the influence of the properties, strength, position and depth of the mesoscale vortex on the acoustic propagation characteristics is simulated by the parabolic equation. Our observed vortex is a typical cyclone-type cold vortex in the Kuroshio extension body, and the cold water turns on intensely at the center of vortex. The effect depth of vortex is 500 m, and then, the parabolic equation of acoustic model is used to analyze and simulate the impact of mesoscale cold-core vortex on acoustic transmission loss. Results show that the horizontal perturbation of the surface velocity caused by mesoscale vortex has a great influence on the spatial distribution of water sound field. The cold vortex makes the position of the convergence zone move forward, with the width reduced, and the gain efficiency enhanced. When sound propagates outside of the cold-core vortex, compared with inside of the cold-core vortex, the assembled areas are backward, with the width increased, and gain effect weakened. The non-uniform hydrological environment caused by the ocean mesoscale vortex is a key modulating factor of the abnormal variation of acoustic energy in spatial distribution.