Ocean acoustic tomography is an appealing technique for remote monitoring of the ocean environment. In shallow water, matched field processing (MFP) with a vertical line array is one of the widely used methods for inverting the sound speed profile (SSP) of water column.

However, most of the MFP inversion methods have been applied to vertical line arrays, which suffer from several drawbacks. In particular, the vertical line array is unsuitable to long term OAT due to its safeness. So LI Fenghua and ZHANG Renhe of State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences carried out a series of studies and investigated the method to invert SSP by MFP with a bottom mounted horizontal line array.

The approach the researchers adopted is to invert the SSP with a bottom mounted horizontal line array (HLA) based on MFP. They use Empirical orthonormal functions to express the SSP and use the perturbation theory in the forward sound field calculation. This inversion method is applied to the data measured in a shallow water acoustic experiment. Successful results show that the bottom mounted HLA is able to estimate the SSP. One of the most important advantages of the inversion method with bottom mounted HLA is that the bottom mounted HLA can keep a stable array shape and is safe in a relatively long period.

This research result was published on the recently issued journal of CHIN. PHYS. LETT. (Vol. 27, No. 8, 2010).