ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2pUW28. Use of empirical orthogonal functions to estimate wave number variance in a stochastic shallow-water channel.

Michael J. Longfritz

William L. Siegmann

Melvin J. Jacobson

Rensselaer Polytechnic Inst., Troy, NY 12180-3590

Mohsen Badiey

Ocean Acoust. Lab., University of Delaware, Newark, DE 19716

The variances of horizontal acoustic wave numbers in stochastic shallow-water environments are estimated using empirical orthogonal functions (EOFs). Using perturbation methods and an adiabatic normal-mode propagation model, the wave number fluctuations are related to range variations in the ocean and/or sediment sound-speed profiles, which can be conveniently and efficiently represented by EOFs. This relationship can be used to estimate both the wave number deviations arising from selected realizations of the stochastic ensemble and the overall wave number variance. The procedure is illustrated by application to a shallow-water waveguide with a multilayered sediment bottom. Both the layer depths and the intralayer sound speeds are modeled as random variables. The accuracy of the estimation procedure is investigated for various choices of the layer depth and sound-speed statistics by comparing with results from computational simulations. A particular environment examined is the New Jersey Shelf Atlantic Generating Site, where relatively extensive geoacoustic profiles are available [M. Badiey et al., 3593--3604 (1994)]. Comparisons are made between results from the estimation procedure and from the KRAKEN and FEPE propagation codes.