Acoustic Calibration in Shallow Water Using Sparse Data

摘要

Conventional numerical techniques for calculating acoustic propagation mayproduce unsatisfactory results if there is insufficient information about the medium. These difficulties are exaggerated in highly variable shallow-water locales. In the proposed approach, sparse environmental measurements are supplemented by making a limited number of direct acoustic measurements. The combined data set can in principle be used to calibrate in-water systems. In this paper, acoustic calibration is demonstrated for the field extrapolation problem where the objective is to predict propagation over an extended regime. Two alternative versions of the extrapolation algorithm are first postulated and then verified analytically for the special case ot adiabatic propagation. The methed is then tested numerically using archival sound-speed and bathymetric data for a strongly range-dependent site. The individual and cumulative effects on down slope propagation from variations in bathymetry, imperfect knowledge of the sediment, and variability in the water column are quantified. (AN).