In SLICE89 broadband acoustic signals were transmitted from a 250-Hz source to a 3-km-long vertical line array of hydrophones 1000 km distant in the eastern North Pacific Ocean during July 1989. The term "SLICE" refers to the vertical 'slice' of ocean that was sampled by the acoustic ray paths. Dr. Mercer proposed this experiment as a stepping stone toward the more ambitious multi-slice sampling techniques to be employed in the Moving Ship Tomography (MST) experiment. The SLICE89 experiment was unique in combining a vertical receiving array that extended over most of the water column, extensive concurrent environmental measurements, and techniques designed to measure acoustic travel times with 1-ms precision. In addition to being the first experiment to clearly image steeply propagating wave fronts, the results led to a better understanding of the impact of internal waves on shallow angle wave fronts. The very precise results of this experiment were also used to improve empirical equations for the speed of sound in sea water. Primary collaboration was with the Scripps Institution of Oceanography and the Marine Physical Laboratory, UCSD. The project was sponsored by the Office of Naval Technology.
Worcester, P.F., B.D. Cornuelle, J.A. Hildebrand, W.S. Hodgkiss, T.F. Duda, J. Boyd, B.M. Howe, J.A. Mercer, and R.C. Spindel, A comparison of measured and predicted broadband acoustic arrival patterns in travel time-depth coordinates at 1000-km range, J. Acoust. Soc. Am., 94, 3118-3128, 1994.
Cornuelle, B.D., P.F. Worcester, J.A. Hildebrand, W.S. Hodgkiss, T.F. Duda, J. Boyd B.M. Howe, J.A. Mercer, and R.C. Spindel, Ocean acoustic tomography at 1000-km range using wavefronts measured with a large-aperture vertical array, J. Geophys. Res., Oceans, 98, 16,365-16,377, 1993.
Duda, T.F., S.M. Flatté, J.A. Colosi, B.D. Cornuelle, J.A. Hildebrand, W.S. Hodgkiss, P.F. Worcester, B.M. Howe, J.A. Mercer, and R.C. Spindel, Measured wavefront fluctuations in 1000 km pulse propagation in the Pacific Ocean, J. Acoust. Soc. Am., 92, 939-955, 1992.
Howe, B.M., J.A. Mercer, R.C. Spindel, P.F. Worcester, and T.F. Duda, SLICE89: A single slice tomography experiment, in Oceanic Variability and Acoustic Propagation, edited by John Potter and Alex Warn-Varnas, pp. 81-86, Kluwer Academic Publishers, Dordrecht, The Netherlands, 1991.