Effect of Surface Duct on Pulses Propagating in a Sound Channel in the Ocean

• Published in: JPN J APPL PHYS PART 1 REGUL PAP SHORT NOTE REV PAP Vol. 40; no. 5S; pp. 3807 - 3810
• Main Authors: Kohji Futa, Kohji Futa, Keizo Ando, Keizo Ando, Toshiaki Kikuchi, Toshiaki Kikuchi, Toshio Tsuchiya, Toshio Tsuchiya
• Format: Journal Article
• Language: English
• Published: 01.05.2001
• Subjects: Acoustic wave propagation; Acoustic waves; Approximation theory; Correlation methods; Fourier transforms; Mathematical models; Time series analysis; Tomography
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.40.3807

In ocean acoustic tomography, unexpected changes in the travel time of acoustic pulses can sometimes be observed. It is considered that the possible causes are internal waves, layered sound speed microstructures and surface ducts. In this paper, we analyze the effect of a surface duct on a pulse that is propagating in a sound channel in the ocean by using the parabolic equation (PE) method. The received pulses change sensitively when a surface duct exists above the sound source or the receiver that is located around the axis of the sound channel. It has little effect on the pulses when it is located in the area between the source and the receiver. Consequently, one should pay attention to the sound speed profile near the surface above the source and the receiver in ocean acoustic tomography.