Searnount effects on long range acoustic propagation in the West Pacific

Acoustical oceanography depends highly on identification of eigen rays and accurate measurement of arrival times of the incoming rays. In particular, it is the case for the long-range propagation at the SOFAR (SOund Fixing and Ranging) channel. However, there are several candidates for disturbing the incoming wave trains such as internal waves, ocean currents and scattering at a seamount. We perform a series of numerical simulations of the long-range acoustic propagation to evaluate the scattering at a seamount. We find that even if the top of the seamount is 2000 m below the SOFAR axis, strong scattered signals still comes up to the arrival record at the SOFAR axis. This shows the possibility that scattered signals at the ocean bottom contaminate the wave trains recorded at the SOFAR axis.