A theoretical and simulation study of acoustic normal mode coupling effects due to the Barents Sea Polar Front, with applications to acoustic tomography and matched-field processing

Abstract

Normal mode coupling due to a shallow water coastal front is considered, using oceanographic data from the 1992 Barents Sea Polar Front (BSPF) experiment as input to normal mode and parabolic equation (PE) acoustic propagation models. Criteria for the sensitivity of mode coupling to coastal front widths are derived, and applied to the BSPF as a representative example. The effects of coastal fronts on tomographic schemes are considered, particularly in terms of travel time-based tomography. The effects of frontal mode coupling on matched-field processing schemes are also considered, using both the maximum likelihood and variable coefficient likelihood methods, which show differing sensitivities to mismatch. Finally, directions for future research are discussed.