Vertical array matched‐field/mode processing results from marginal ice zone data

Matched-field/mode processing (MFP) has been used to successfully detect and localize submerged acoustic sources in shallow water, arctic waters, and open ocean environments. A very challenging environment for the application of these techniques is the marginal ice zone. The spatial and temporal oceanographic variability of this region makes precise acoustic modeling impossible with the modeling techniques commonly available today. Hence, successful MFP in the marginal ice zone requires the use of robust processing schemes that can perform satisfactorily in an inherently mismatched environment. In this paper, successful MFP results are reported for marginal ice zone data from a vertical, near-surface array deployed as part of the MIZEX-88 experiment. A robust, dimensional reduction processing scheme, the reduced maximum likelihood method [Byrne et al., J. Acoust. Soc. Am. 87, 2493–2502 (1990)] applied to a few of the low-order modes, was used for successful localization of a 190-dB source at a range of 9 km, with some depth error, using measured environmental parameters. The depth error was eliminated by refinements made to the environmental and array element location parameters. [This work is supported by the AEAS program.]