## 2pUW14. Obtaining the ocean index of refraction spectrum from the acoustic amplitude fluctuations.

### Session: Tuesday Afternoon, December 3

### Time: 4:56

**Author: Terry E. Ewart**

**Location: Appl. Phys. Lab., Univ. of Washington, Seattle, WA 98105**

**Author: Stephen A. Reynolds**

**Location: Appl. Phys. Lab., Univ. of Washington, Seattle, WA 98105**

**Author: Daniel Rouseff**

**Location: Appl. Phys. Lab., Univ. of Washington, Seattle, WA 98105**

**Abstract:**

Ewart and Reynolds [Wave Propagation in Random Media (Scintillation),
edited by Tatarski, Ishimaru, and Zavorotny (SPIE, Bellingham, WA, 1993), pp.
100--123] provide a convincing comparison between the ocean spectral model
determined from a stochastic inverse using the acoustic phase spectrum (measured
in the Mid-ocean Acoustic Transmission Experiment) and the same model derived
from oceanographic data. The success of using the acoustic phase for such
inverses is based on the high accuracy of Rytov theory to predict the phase
spectrum. Accurate measurement of the acoustic phases (travel times) requires
fixed sources and receivers, an experimental complication. If it were possible
to use Rytov theory for the amplitude fluctuations, the experiment complexity is
much reduced and simpler moorings could be used. In this talk results are
presented from a study of the viability of this approach using numerical
simulations of propagation through internal waves to a vertical array of
receivers. With the only requirement being applicability of the Rytov
approximation, two-dimensional (depth/time) correlations of the oceanographic
model are obtained by stochastic inversion and compared to the input internal
wave model. The importance of this result to augmenting oceanographic
measurements, and a discussion of the future possibilities, are presented. [Work
supported by ONR.]

ASA 132nd meeting - Hawaii, December 1996