David H. Berman
Dept. of Phys. and Astron., Univ. of Iowa, Iowa City, IA 52242
Provided mode amplitudes are uncorrelated with one another, it is possible to extract sound-speed information from the covariance of the pressure field along a vertical array [D. H. Berman and S. N. Wolf, J. Acoust. Soc. Am. 91, 2447(A) (1992)]. Conditions under which modes are in fact uncorrelated will be discussed here. In addition, a method for correcting effects of array tilt will be presented. The main difficulty of the extraction scheme is that second derivatives of the covariance are required. Various attempts at smoothing data, including fitting the covariance matrix to Pekeris normal modes will be described. The method will be applied to covariance matrices assembled from data gathered near San Diego in 1985. [Work supported by U. S. Naval Research Laboratory.]