Prediction of the effect of range dependence on convergence zone levels

Abstract

Convergence zone propagation in a range‐dependent environment typified by fronts and eddies is considered. This study addressed the effect of these mesoscale anomalies on convergence zone levels, in particular to determine when catastrophic signal losses may result. Through use of a range‐dependent Snell's Law the effects arising from the explicit changes in sound speed as well as implicit effects arising from the presence of horizontal sound speed gradients are quantified. A simple method is developed to first identify whether a mesoscale feature leads to catastrophic losses, and then to determine source position relative to the feature where these losses may be realized. Parabolic equation propagation simulation through a Gulf Stream Eddy Model simulation are then used to present illustrative examples and confirmation of the theory. [Work supported by Department of the Navy.]