Some Bottom-Reflection Loss Anomalies near Grazing and Their Effect on Propagation in Shallow Water
The bottom-reflection loss near grazing from a hard bottom, or from one that has a hard sub-bottom, can in certain cases be fairly high. This can result in higher propagation losses in shallow water than are usually expected. Two frequently observed cases have been studied, one where the bottom can propagate shear waves and another where the bottom is covered by a layer of soft unconsolidated sediments. The first case causes a low-frequency attenuation whereby an optimum frequency is created for the propagation, whereas the second case creates selected frequencies for which the propagation is poor.
KeywordsShear Wave Critical Angle Transmission Loss Reflection Loss Grazing Angle
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- 1.L. M. Brekjovskikh, “Waves in Layered Media”, Academic Press, New York, N.Y. (1960).Google Scholar
- 2.F. B. Jensen and M. C. Ferla, SNAP: the SACLANTCEN normal-mode acoustic propagation model, SACLANTCEN SM-121, SACLANT ASW Research Centre, Italy (1979). [AD A 067 256]Google Scholar
- 3.F. B. Jensen and W. A. Kuperman, Environmental acoustic modelling at SACLANTCEN, SACLANTCEN SR-34, SACLANT ASW Research Centre, La Spezia, Italy (1979). [AD A 081 853]Google Scholar
- 4.E. L. Hamilton, Acoustic properties of the sea floor: A review, in: “Ocean Acoustic Modelling”, W. Bachmann and R.B. Williams, eds., Proceedings of a Conference at La Spezia, Italy, 8–11 Sep 1975, Part 4: Sea bottom, SACLANTCEN CP-17, SACLANT ASW Research Centre La Spezia, Italy (1975), pp. 18–1 – 18–96. [AD A 020 936/1G1]Google Scholar