Research And Application Of Seafloor Parameters Inversion

Acoustics is the only propagation energy for long distance underwater. The acoustical parameters, like velocity, density, attenuation, structure et al, are very important for the sound field prediction in shallow water, location of MFP and covert selection of submarine. The studying about acoustic characters of sediment has been a important problem to the department of defense. Another, the acoustical parameter of seabed are important information to ocean engineering.In this paper, the inverse arithmetic of seafloor, and application of classification of seafloor is done. A composite inverse method integrating the stripping method and optimization theory is given. At first, the impedance of seafloor is estimated through stripping method, and then the velocity and density are separated by combining the Hamilton experimental formulas. The attenuation is extracted by the spectrum of the layers at different depth. Now, the initial model of seafloor is founded. At this fundamental modal, the optimized solution of seafloor is given by the optimization theory. The composite method overcome the disadvantage of optimization theory which the initial model is based on priority knowledge. To get the correct stable impulseresponse, a composite criterion and sectional stripping inversion is given. In the forward procedure, the forward method including the attenuation of layers is given.For validating the inversion, the experiments were carried out in Yellow Sea in 2001 and 2002. In the later experiment, the sampling experiment of seafloor is done. Another, I took part in the project 0206 in 2002, got some seafloor data. Through these experiments, higher solution (30cm level), lower errorless 9%) of impedance profile/velocity profile/density profile are achieved.The results of acoustical parameters inversion is taken in to identify the seafloor style. The results are well agreement with the sampling data. A character of impedance profile is extracted by fractal decomposition. This character is taken as a parameter to distinguish the sand or silt style.