1 \ r 



120 60 



FIGURE 19 A comparison of power spectra of simulto 

 corrected for instrument response. 



neter records, 0215 — 0345Z, 3 June 1 961 —Spectra are 



6. DISCUSSION 



a. The Relationship of Atmospheric Micropressure Fluctuations to 

 Water Waves 



Cross -correlations of many of the simultaneous wave and micropressure 

 records vere computed to see if quantitative relationships coiild be determined. 

 The coherences of these paired records are plotted in figure 22 and meaningful 

 peaks are observed. The coherence values of the peaks seem to have no relation- 

 ship to local wind velocity but appear to be a function of the average local 

 surface wind direction. This can be seen when the coherences of the significant 

 peaks are plotted against the average wind direction observed at the time the 

 records were made (figure 23). Maximum coherences occurred when the wind 

 direction was about l85°T, suggesting that maximum wind-to-wave energy transfer 

 occurs at this location when the wind blows from this direction. 



The dependency on direction could be explained in the following 

 manner. Since the pack ice pressure ridge systems in this area of the Beau- 

 fort Sea had a general east-west trend during this time (Wittmann, 1964), they 

 would offer the greatest resistance to forces moving in a generally north-south 

 direction. Considerably more observations, however, are needed to verify such 

 an hj'pothesis. 



Significant coherences appear only with waves generated at some 

 distance from the recording site. As would be expected, there is no coherence 

 between local wind and the wave motion due to the resonant period of ARLIS II. 



33 



