Effects of source position and frequency on geoacoustic inversion

In this paper, geoacoustic inversion based on simulated annealing and the B DRM propagation model is applied to the test cases from the 1997 Geoacousti c Inversion Workshop. The effects of the bottom parameters on the sound fie ld are discussed theoretically and two characteristic angles dependent upon geoacoustic parameters are defined. Based on the theoretical analysis of t he characteristic angles, a multi-frequency inversion scheme is given as fo llows: High frequency and farfield data are used to invert the upper bottom parameters first, and then low frequency and nearfield data are used to in vert the lower bottom parameters. Simulated tests show that the results of multi-frequency inversion are more accurate and reliable than single freque ncy inversion.