Numerical simulations of acoustic backscattering on fractally corrugated Seabed surface

The numerical simulations of echosaunder signals scattering by fractally corrugated sea bed surface are presented. In particular, the relations between fractal dimension, describing the large scale roughness of sea bottom, and received echo envelope shape, were investigated. The fractal large scale relief of seabed suiface was generated assuming the power law form of the spatial frequency power spectrum, with exponent related to fractal dimension, and subsequently applying the two dimensional inverse FFT algorithm. In the secand stage, the bottom echo waveform was numerically modelled as an incoherent sum of coruributing echoes from all surface elements. For each element, the echo amplitude was calculated assuming the form of angular dependence of bottom backscattering coefficient for smal! scale roughness. The obtained results of simulations have revealed same conditions for the transferring of the seabed surface fractal structure onto the shape of echo wavefonn.