Abstract: | A rigorous theory of backscattering from slightly rough, statistically non-stationary surfaces is developed. The development proceeds through the application of two ensemble averages: the first is applied to all realizations of the surface having fixed non-stationary features, and the second over all non-stationary surface characteristics. The resulting theory is applied to acoustic sea-floor reverberation, where it is found that non-stationarity must be assumed to obtain agreement with observed reverberation fluctuations. The analysis is further extended to the time domain where it is demonstrated that, for Bragg scatter, no reduction in the predicted fluctuations occurs for frequency diverse waveforms, thus providing a method of differentiating Bragg scatter from other non-resonant scattering processes. |