MELLEN: SOUND PROPAGATION IN A RANDOM MEDIUM 



and I'd like to take issue with the deep-water results. It's very- 

 difficult over long ranges to accurately compute the transmission loss, 

 and it's known not to be simple cyclindrical spreading in general. 



Dr. Mellen: You're talking about the PARKA results now? 



Dr. Tapper t: PARKA and the South Pacific results. And you 

 showed some results for the Atlantic, deep water. 



Dr. Mellen: Right. That was Thorp's original data set for the 

 North Atlantic. The North Central Atlantic didn't show any scattering. 

 In Thorp's original compilation, there is no scattering at all except 

 maybe a very, very tiny bit at the extremely low frequencies. 



But on the ATOE experiment there was strong evidence of scatter- 

 ing. We can do two experiments. In one experiment we see lots of 

 scattering, and in the other experiment we don't. And it's real. 



Dr. Tappert: I'm sure the effect is real. But whether we can 

 measure it quantitatively and make agreements with theory is another 

 issue. 



Dr. Mellen: Well, let's say using this technique we found the 



boron relaxation — which nobody believed at that time. So now we 



are finding something else besides the boron relaxation. We're talk- 

 ing about finding scatter. 



Dr. Smith: I have a comment which stems from our treatment of 

 some of the Gulf of Maine shallow water data. I thought I'd try some 

 curve-matching to the data. The water was roughly 200 meters deep. 

 We had transmission loss data in third-octave bands at ranges from 

 something like 2 kilometers to 150. I thought I'd match the curve 

 for 1 kHz with the equation 



TL = C + N log R + aR 



for values of N equal to 10, 15, and 20, choosing C and a m each case 



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