An application of a full scattering theory to Arctic propagation

Abstract

The full scattering theory of Burke and Twersky [J. Acoust. Soc. 40, 883–895 (1966)], which includes both the specular and scattered energy for a rough surface consisting of elliptical bosses on a plane surface, is applied to the problem of propagation under the ice surface. This theory has been efficiently parametrized [D. Rubenstein (unpublished manuscript)] for the case of randomly spaced keels with a Rayleigh distribution of depths. The scattering kernel for this treatment has been used in a coupled mode formulation of the ASTRAL propagation model. The modified ASTRAL can compute the propagation associated with both the specular field and the total field which includes the nonspecular component. The redistribution of energy among the modes occurs continuously with range, so the model can display the mode excitation as a function of range. The model is compared to some measured propagation data, paticularly that of Diachok [J. Acoust. Soc. Am. 59, 1110–1120 (1976)], who applied low‐ and high‐frequency ...