MELLEN: SOUND PROPAGATION IN A RANDOM MEDIUM 



of something per unit frequency band. 



Dr. Ira Dyer (Massachusetts Institute of Technology) : 

 That's mislabeled actually. 



Dr. R. R. Goodman (Naval Research Laboratory) : On your last 

 picture (Figure 18) where you showed the areas of anomalously high 

 absorption, with the exception of the Gulf of Aden, they are all 

 shallow water results, aren't they? 



Dr. Mellen: Baffin Bay is also deep water. 



Dr. Goodman: How deep is it? 



Dr. Mellen: About 2,000 meters. 



Dr. Goodman: One thing I would like to point out with respect 

 to the Hudson Bay results and perhaps Lake Superior as well as any 

 shallow water. You are putting a tremendous amount of faith in the 

 shallow-water propagation loss that you are taking out of these data. 

 If you are talking about shallow-water propagation over a hundred miles 

 you are talking about an accuracy out to a hundred miles of 5 decibels 

 in the model, and that's better than any model I know today for 

 shallow water. 



Dr. Mellen: Again, all we do is linear regression to the data. 

 We don't worry about absolute values or how it got there. We start 

 at very long distances. For instance, in Baffin Bay we measure only 

 from 100 kilometers to 400 kilometers in that region. And the 

 propagation is extremely well behaved, and you really believe the 

 results. 



Dr. Goodman: You're subtracting off a transmission loss term. 

 You have to be . 



Dr. Mellen: Subtracting out cyclindrical spreading. 



Dr. Goodman: Right. Do you have faith in cyclindrical spread- 



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