Dispersion and ranging of transient signals in the Arctic Ocean

A method of estimating the source to receiver range of wideband underwater acoustic pulses is critically examined in this paper. The method is based on the time–frequency dispersion of broadband signals received at a single hydrophone. Shot data recorded at field locations in the Arctic are analyzed by this technique. The resulting range predictions are compared with the observed ranges. Good agreement is found for those cases in which the bottom depth along the propagation path is greater than 1 km. At these depths, the upward refraction feature of Arctic sound propagation minimizes the effects of bottom topography. As long as the signal is above the noise level, the method is insensitive to the type of background noise and to the source spectrum shape. The frequency dispersion for an N2 bilinear sound-speed profile is investigated analytically. This profile yields a very close and useful approximation to the Arctic underwater sound field. The results are used to interpret the experimental data and to identify the factors which may influence the range estimation method.