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

• Main Authors: Herstein, Peter D., Cole, Bernard F., Browning, David G., Kanabis, William G.
• Other Authors: NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
• Format: Text
• Language: English
• Published: 1993
• Subjects: Acoustics; *ACOUSTIC WAVES; *ACOUSTIC ATTENUATION; *TRANSMISSION LOSS; *UNDERWATER ACOUSTICS; FREQUENCY; PATHS; DEPTH; GRAZING; BOTTOM LOSS; WAVE PROPAGATION; REFRACTION; RECEIVERS; SHALLOW WATER; SENSITIVITY; ANGLES; GRAZING ANGLES; Long Island; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA274343; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA274343

Under downward refracting conditions, raypaths from a shallow source will tend to have grazing angles at a hard bottom that are greater than the critical angle arid, 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 tor ranges up to 50 km. The results are compared to the previous results of Cole and Podeszwa (B. Cole and E. M. Podeszwa, J. Acoust. Soc. Am. 41, 1479-1484 (1967)). Shallow water, Optimum frequency, Source-receiver placement, Environmental dependence, Environmental acoustics.