SPINDEL: PHASE FLUCTUATIONS, COHERENCE AND INTERNAL WAVES 



The point I wanted to raise is that phase, even in a frozen 

 deterministic ocean, is not linear in range. And I am concerned with 

 techniques which remove a linear phase trend and assume that the 

 residual fluctuations are due to internal waves or other random- 

 ocean effects. 



In summary, there is a natural non-linearity in phase in the 

 ocean. 



Mr. M. A. Pedersen (Naval Undersea Center) : You took out a 

 constant velocity, didn't you? 



Mr. Spofford: I accumulated a phase for the entire range. 



Mr. Pedersen: Yes, but you removed it by taking out a constant 

 phase velocity? 



Mr. Spofford: Yes. Essentially. 



Mr. Pedersen: And as you move into different parts of the con- 

 vergence zones you have different phase velocities because you have 

 different vertical angles. 



Mr. Spofford: Absolutely. 



Mr. Pedersen: So it will progress this way. 



Mr. Spofford: I was expecting to get phase variations. The 

 question I was not sure of was how quickly they might change with 

 range . 



Now, his measurement only went over a fraction of a mile, I think, 

 in range. So I do not think it is driving the problem in terms of the 

 kinds of things he measured. I think it will introduce a variation 

 or non-linearity in phase on the order of about one cycle at 400 Hz. 



458 



