M 



1 



1 III 



II 1 1 





1 



1 1 



1 









/^\.-'-\ 















/x 



/ \ PACK ICE 















1 I 

 1 1 

 1 / 



\ \ 

 \ \ 



ARLIS n\ \ 





95» 



CONFIDCNCE 



LIMITS 





\ 







y'/ 



\ \ 



\ \ 













\ 



\ 

 \ 



(a) 



/ / 

 / / 



/ 3 JUNE 1961 

 -/ 0300-0345 H 



\ \ 

 \ \ 

 \ \ 

 \ \ 



/N 





N/" 



/\ 



C/ 



.6 



176 



h 



.r 



113.2* 



272.8* 





247.3* 





.5 



/ 





(\ 



j \ 95% CONFIDENCE 



219.6* 



/\ 



2.0» 



A, 



a. -3 



/ 



n 



\ 



/a a 



I 



.A 



^\/ 



8-2 



.1 







/ 



V ^ 



\ 



r-'^m 



^V 





V 



167 



1 1 1 



38.5 



1 1 



27 g-* — PERIOD (SEC) 



r 1 1 1 



14.3 



12.2 



1 1 



11.1 



1 1 



/ 



u\ 



.01 .02 



.0 



.04 .06 .06 



.07 



.08 



.09 .It 



(b) 



FIGURE 9 (a) Power spectra of simultaneous grovimeter records 

 (b) Coherences for these records 



plotted in figures 8b and 9ti. The same analysis described by Munk et al . 

 (1963) for a 2-eleinent array to measure swell in the Pacific Ocean was then 

 applied to the present data. 



b. Direction Finding 



Figure 10 shows placement of the array on 3 June I96I. The phase 

 relationships given in figures 8b and 9b show that the energy passed the 

 north (n) station before the south (s) station. With only two elements in 

 the array, an ambiguity of wave directions is inherent. The waves may be 

 coming either from the west or the north. Examination of the weather maps 

 just prior to and during the wave recording shows a strong storm system 

 centered over Siberia (figure 11). Strong southerly winds were indicated 

 over the western Chukchi Sea. On the other hand, the northern part of the 

 Arctic Basin appears calm. It was therefore assumed that the observed waves 

 were associated with the Siberian storm and were coming frcan the west. Con- 

 sider, then, an elementary wave train of freq[uency f coming from a direction 

 a measured clockwise relative to the azimuth of the normal to the array 

 (233°T). The signals observed at the S and K gravlmeters, respectively, 

 could be written as 



77 = A cos (2 77- ft - 0) 

 17^ = A cos (2 7rft) 



n 



21 



