ASA 125th Meeting Ottawa 1993 May

5aUW12. Matched-field estimation of scattering from Arctic ice---Analysis of the CEAREX 89 field experiments.

Tarun K. Kapoor

Henrik Schmidt

Dept. of Ocean Eng., MIT, Cambridge, MA 02139

Scattering experiments were conducted in 1989 in the Norwegian--Iceland Sea using explosive charges detonated at varying depths. The scattered field was received at a crossed horizontal hydrophone array positioned at a depth of 60.0 m. In this paper, the scattering of low-frequency acoustic waves from the Arctic Ice sheet will be evaluated via matched-field processing of short-range returns. Using near-field beamforming (focusing), which assumes a point scatterer, it was possible to isolate the scattering hot spots under the ice sheet. Essential inputs to this processing include the source location and shot times which were determined using an adaptive least-squares estimator in a matched-field approach. [Work supported by ONR.]