Adiabatic mode theory of underwater sound propagation in a range-dependent environment

Abstract

For an ocean sound channel whose environmental parameters depend not only on depth, but in a gradual fashion also on range, the wave equation may be separated by the adiabatic range variation method of Pierce [J. Acoust. Soc. Am. 37, 19 (1965)]. This method is used here to calculate underwater sound propagation in a channel with arbitrary (but gradual) range dependence, and also with arbitrary depth dependence of the sound velocity profile, by employing Airy function solutions of segmentwise linearized problems. Our results are illustrated for a realistic deep-water propagation case with profile data collected in the western North Atlantic, as well as a shallow-water example from the Norwegian Sea, and compared against the experimental transmission loss data, and the results of calculations using other methods for the same cases.

Analysis of modal evolution caused by a weakly range-dependent seabed in shallow water and its application to inversion for geoacoustic properties

“…At this point, by exploiting the WKBJ approximation method and matching the boundary condition close to the source, we obtain an adiabatic mode solution in the following form [62,63]: As seen from a comparison of the field given by normal mode sum in Eq. (2-6) and the field given by adiabatic mode sum in Eq.…”

Propagation in a tropospheric duct with a single-step discontinuity in the refractive index in the direction of propagation

“…In (19) H (1 ) and H (2 ) are Hankel functions of the first and second kind. VV where a 1 is the height where the refractive index changes from k to k where…”

“…Knowing Rl(v), R 2 (v) and cx(v) allows us to solve for T(v) in (19), again using the continuity of g at r=a 1 and we obtain…”

Spatial coherence and rough bottom scattering in shallow water

“…Bellis [77] and McDaniel [75] have studied coupled mode approach on rough surface scattering. The mode coupling theory applied on the range dependent environment has been studied by some authors [69,[72][73][74][75]78].…”