The simulation of underwater acoustic propagation with the horizontal changes of sound speed profiles

In the simulation of underwater acoustic propagation, sound speed is usually characterized by the vertical distribution of the sound speed profile (SSP), but it ignores lateral variation. This paper carried out simulation on constant SSP, negative and positive gradient profile, and real sound speed profiles (SSPs), concerning a Gulf Stream scenario, and by using Bellhop model. The characteristics of underwater acoustic propagation in the horizontal direction are discussed. The results show that the changes of sound velocity in the horizontal direction have a certain effect on underwater sound propagation. With the horizontal sound speed increasing for the steady SSPs, the number of eigenrays increase, and the transmission loss and the arrival times decrease. Conversely, the number of eigenrays decrease, and the transmission loss and the arrival times increase. With the horizontal changes of the unsteady SSPs, underwater acoustic propagation is basically followed by this law, but the transmission loss may change suddenly in some cases. It has a certain reference value for underwater acoustic modeling. Further work will be discussed and analyzed in the future.