The Role of Nowcast and Forecast Input Parameters for Range Dependent Transmission Models

Abstract

The Maritime Operations Division of DSTO is assisting the Royal Australian Navy in its assessment of a sonar performance prediction tool for range dependent ocean environments: TESS 2, prepared by Thaïes Underwater Systems. This assessment has included comparisons between acoustic transmission loss data measured by MOD at shallow ocean sites with range-dependent transmission predictions obtained by TUS. Part of this task has been the inference of the appropriate input parameters from the measured data and comparison with historic data sets. This applies to bathymetry and to seafloor acoustic properties. Examples detailed in this paper indicate the variability in properties which must be described at differing regional locations and the difficulty that can occur at arriving at suitable input parameters from historical data alone. These examples include reference to high resolution bathymetry (ocean depth) data, and the inference of seafloor reflectivity based on received signal data.