MELLEN: SOUND PROPAGATION IN A RANDOM MEDIUM 



DISCUSSION 



Dr. D. C. Stickler (APL, Pennsylvania State University) : 

 Referring to Figure 17, what was the difference between the correlation 

 that fell off rapidly and those that didn't? 



Dr. Mellen: Two hydrophones at Bermuda were separated in the 

 vertical. The correlation between the two of theni was measured as 

 a function of the separation distance. The dashed curves are from 

 Chernoff estimating at 100-feet and 200-feet correlation distance. 



Dr. P. W. Smith (Bolt, Beranek, & Newman, Inc.): You picked out 

 my favorite example of something I completely fail to understand. 

 They have here a single path going up which may be significant on a 

 ray picture vertexing 124 feet, I think it was, below the surface, 

 then going down to the bottom, coming in at very shallow grazing 

 angle. And what I completely fail to understand is how they can get 

 such high correlation in the arrivals — in the phase or arrival 

 times — over their separation between the transducer pairs and this 

 very short correlation interval in the amplitudes. Does anyone have 

 any guesses? 



Dr. Mellen: I can't answer that question. I only used this to 

 illustrate the correlation distances to compare with the 15 meters 

 that we measure in the Mediterranean and the Hudson Bay. 



Dr. Smith: I don't think that the behavior of the time and 

 amplitude would be consistent with the theory with which it is being 

 compared. 



Dr. Walter H. Munk (Institute of Geophysics and Planetary Physics, 

 Univ. of Calif., San Diego): There is something else I completely 

 don't understand, and other non-acousticians who have looked at your 

 results are equally confused. Figure 16 has power spectral densities 

 in dB, and I don't understand those units. Spectral density is units 



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