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

2pUW18. Probabilistic range dependence in a numerical average underwater acoustic propagation method.

Roger M. Oba

Naval Res. Lab., Stennis Space Center, MS 39529-5004

A computational method for forward propagation of the Helmholtz equation has been developed for numerically computing average complex pressure field in a single pass. It used sound-speed profiles be piecewise probabilistically independent in finite sized range steps to calculate transmission loss and phase for the average solutions in the continuous wave case. This required that the uncertainty is probabilistically modeled within range intervals as ensembles of sound speeds which were independent from one range step to the next. This method can be modified to represent certain cases for which there is statistical dependence in range. This can be achieved by nonlocal averaging over several range steps. The inter-relation of range sound speed and statistical dependence will be considered, and results from numerical experiment will be shown. Similar calculations allow the calculation of growth of standard deviation over range. This modification can also be considered in the limit of small intervals of uncertainty. [Work supported by Naval Research Laboratory and the Office of Naval Research.]