Sensitivity of Shallow Water Transmission Loss to Source and Receiver Proximityto a Hard Bottom Under Downward Refracting Conditions

摘要

Under downward refracting conditions, raypaths from a shallow source will tend tohave grazing angles at a hard bottom that are greater than the critical angle and, therefore, suffer a relatively large loss per bounce . As the source depth increases, lower grazing angles can be obtained. When the grazing angle becomes less than the critical angle, bottom loss per bounce is significantly reduced, allowing a possible reduction in propagation loss. An analysis is made for a North Atlantic shallow water area south of Long Island under summer conditions to determine the sensitivity of transmission loss to changes in source and receiver depth for ranges up to 50 km. The results are compared to the previous results of Cole and Podeszwa (B. F. Cole and E. M. Podeszwa, J. Acoust. Soc. Am. 41, 1479-1484 (1967)). Shallow water, Optimum frequency, Source-receiver placement, Environmental dependence, Environmental acoustics.