100 .01 



cph 



cph 



FIG. 7, Computed (smooth curves) aad observed spectra of phase (left) and intensity (right) at Cobb Seamount. Only the 4-kHz 

 results are shown for phase; at 8 kHz computed and observed values both are higher by 6 dB. 



<«>-((f); 



{j'^)(fBRwt,noJ2 



xZ l[F2'(0) + FJ(r,)] 



ZA9, 



The summation ;' extends over 34 rays in the order of 

 decreasing inclination 6, of the axial source. For even 

 numbers of loops, values of ±9,- pair with precisely the 

 same statistics, but for odd numbers of loops there is 

 an extra upper loop for positive 9 and an extra down- 

 ward loop for negative 6. Each ray is weighted accord- 

 ing to the difference AS, between adjoining rays, and 

 this emphasizes the near axial rays. 



The number of loops varies from 60 {K' = 30, K" = 30) 

 for the near-axial rays (^ = ±1°) to 44 (/C' = 22) for the 

 surface- limited rays. The largest y^ is at the central 

 loop, x = jR, >' = i?/4B^? = 0. 184 and even then the differ- 

 ence between F^iy) and F2(0) is slight. We may then 

 use the geometric optics formula 



<<^?) 



<my'-' 



>(7^Bfla),„«o, 



SAe, 



x[K'Fi(0) + K'Fl{0)] . 



The sumand (last column of Table VII) is fairly uni- 

 formly distributed among all contributing rays. 



The agreement between computed and measured val- 

 ues of {(^f > is rather too good. 



TABLE VI. Measured and computed MIMI parameters. 



Midstation 



Bermuda 



Apex approximation, SLR 4. 6x10^ sec- 



Weighted average 



3.5x10"-' sec 



6. 8x 10"^ sec-' 

 5.2X :0"' sec"' 



230 



