MELLEN: SOUND PROPAGATION IN A RANDOM MEDIUM 



Mr. Martin: When he did that work in the PARKA exercise he did 

 find he didn't get any difference. 



Mr. Smith: Of course, those are two experiments which are parti- 

 cularly well designed in nice deep water, good channels and good 

 measurement positions. Also, we want to remember the recent work 

 that was interpreted as showing negative bottom reflection losses. 

 We have got to bring all our information about the physics together, 

 it seems to me, and make a consistent whole of it. 



Mr. Pedersen: There is a problem with using peaks of convergence 



zones to do this because if you include the diffraction correction, 



5/3 

 the loss drops off as R 



Mr. Martin: But it isn't a convergence zone. It's the SOFAR 

 shape. While there is a lot of rays in there that are adding coher- 

 ently and somewhat incoherently, you're doing regression analysis to 

 get rid of the incoherent. 



Mr. Pedersen: If you look at one caustic in the convergenze 



zone and you identify it in the first one and second one, and so on, 



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 that level drops off as R 



Dr. Mersey: I think I'll make one attempt to bring the wrath 

 of everybody down on my head because this particular controversy has 

 been bubbling in our community for some time and it has seemed to me 

 that as we have talked about it and as new results have become avail- 

 able from various parts of the world, some very imaginative choices 

 have been made of experimental locations, and there is an excellent 

 body of data available from just the group at New London that has 

 done so much of this work, and there are other data samples like the 

 PARKA set that they participated in, all of which are sufficiently 

 well documented to see what the attenuation coefficient is as a 

 function of the data analysis model. 



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