it alone is representative of the Arctic Ocean Basin. The thick ice island 

 is an anomaly and, especially because of its resonance, appears to behave 

 differently than the pack. 



The vertical pressure cr needed to bend an elastic plate of thickness 

 h is given by 



O" tr = 



-Eh^ dV (22) 



2 it- 

 12(1 - ^ ) 4!C 



If the plate is bent about a central plane into the form of equation (l8) then 



^ -^Eh^"^ A 3in {2yr^) (23) 



3(1- A^'')X^ 



Computations of cr^ for a short-period component appear most useful 

 because: (l) the required bending pressure will generally be greater, the 

 shorter the period; and (2) the shorter period waves are more likely to have 

 been generated closer to the recording site owing to the significant attenua- 

 tion that they undergo ( cc l/ X^) compared to the longer periods. Furthermore, 

 it appears from section 6a above that atmospheric energy can be added along 

 the wave path. Presumably, then, the shorter the wave period, the shorter the 

 distance between generating area and receiving site. Therefore, comparison of 

 the force of the short-period micropressure waves with the short-period ocean 

 waves would probably be most meaningful. 



From figure 25 showing the "displacement" spectra of the two simulta- 

 neous time series, the 11.1-second ocean wave component was calculated to 

 induce an average displacement of the pack ice of 0.001cm between 0215 and 

 0345Z. For a wave period of 11.1 seconds, X = 193m, and the maximum stress 

 necessary to bend the ice (from equation (23)) is 0,8 dynes/cm^. 



From figure 16, the 11.1-second component of the micropressure 

 spectriam (0215 to 03i+5Z, 3 June I961) was found to have an average value of 

 22. i^ dynes/cm2 or 28 times the theoretical force necessary to bend the ice 

 sinusoidally with the observed displacement. This rough calculation suggests 

 that there is ample energy in the micropressure waves to completely explain 

 the water water generation beneath the ice, even at relatively low wind speeds 

 (8 knots in this case). 



7. CONCLUSIONS AM) RECOMMEITOATIOKS FOR FURTHER WORIC 



Waves of the swell type are generated in the Arctic Ocean Basin and 

 are associated with storms as are those in the open ocean. The thin, elastic 

 ice cover in the Arctic limits considerably the maximum amplitude that the 

 swell can have and drastically attenuates waves in the period range usually 



39 



