| Popis: |
Accuracy of relative intensity and horizontal wave‐number predictions from parabolic approximation models of shallow water, low‐frequency (less than 100 Hz) acoustic propagation problems is examined. Effects of input parameter uncertainties and basic approximations in parabolic equation models are investigated. Environmental parameters and uncertainties considered correspond generally to those from a recent New Jersey Shelf experiment. Parameter uncertainties are found to impose the greatest limitations on prediction accuracy, with sediment sound‐speed uncertainties causing the largest restrictions. Issues associated with modeling the sediment sound speed, such as using isospeed layers to approximate sound‐speed variations, are also resolved. Weak range dependence in the channel depth and sound speed, of similar type as at the experiment site, is found to be well approximated by range‐independent models. Comparisons of the experimental results with model predictions illustrate how parameter uncertainties ... |
