ANDERSON: BOTTOM PROPERTIES FOR LONG-RANGE PROPAGATION PREDICTION 



REFERENCES 



Bucker, H. P., "Sound Propagation Calculations Using Bottom Reflection 

 Functions," in Physics of Sound in Marine Sediments, L. Hampton (ed.). 

 Plenum Press, 1974. 



Hamilton, E. L., "Geoacoustic Models of the Sea Floor," in Physics 



of Sound in Marine Sediments, L. Hampton (ed. ) , Plenum Press, 1974. 



Horton, C. W. , These Proceedings. 



Urick, R. J., "Underwater Sound Transmission Through the Ocean Floor," 

 in Physics of Sound in Marine Sediments, L. Hampton (ed.). Plenum 

 Press, 1974. 



DISCUSSION 



Mr. Charles Spofford (Office of Naval Research) : What value do 

 you get by extrapolating Figure 7 to 100 Hz? 



Dr. A. L. Anderson: About 0.026 dB per meter, something like 

 that. 



Mr. Spofford: We have seen data in certain areas where there is 

 a very thick unconsolidated sediment. Assuming a 20-degree ray and a 

 refracting gradient of one in the bottom, the ray spends about 1,000 

 meters in the bottom per bounce . 



We have seen data where essentially that ray appears to have 

 bounced up to about 10 or 20 times even out to 200, 250, and 300 miles 

 without suffering appreciable loss. Figure 7 would lead to about 

 20 dB in 200 miles. I would say if it has lost anything it might be 

 about 2 dB. It is that little. 



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