MELLEN: SOUND PROPAGATION IN A RANDOM MEDIUM 



were already beyond the region where the bottom is important. What 

 other mechanism is there if there isn't cylindrical spreading? 



Dr. Smith: Well, I agree with you if you accept conventional 

 wisdom that the bottom strips everything off and there are no contri- 

 butions left and if then you accept that the ocean is homogeneous 

 you're going to get cylindrical spreading. There are situations 

 where I know some of those assumptions are not right. 



Dr. Weinberg: Right, but we are not talking about those 

 situations. We are talking about very carefully planned experiments 

 where we are sure to put things right on the axis or as close as 

 possible . 



Dr. Smith: Gulf of Maine may not be one of those you want to 

 point at then. 



Dr. Tappert: One problem. The very theory that explains this 

 scattering attenuation predicts that the fluctuations will also fill 

 in modes as they are stripped off. As some are stripped off, others 

 are filled in by the random fluctuations. So you are not left with 

 just the single mode. Therefore, the attenuation without the 

 scattering will not be purely cylindrical. 



Dr. Goodman: We are talking about a very tiny effect on a 

 large propagation, and what we really have to do is determine the 

 confidence limits we have on what is left over, I think the only way 

 this will ever become convincing to anyone is to have a very careful 

 analysis of all of the elements that contribute to the total loss and 

 some sort of error analysis on how well you can trust your models. 



Most of us don't have that kind of faith in our models. I think 

 it's up to you to put down some numbers so that the confidence limits 

 are valid for taking a guess. We would certainly like to see something 

 like boron. It's an interesting problem. But the question really 



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