d. Evaluation of the Resiolts of the 2-Eleinent Array 



Probably the most significant conclusions that can be dravn from this 

 experiment are (1) that waves in the Arctic are generated by storms as are 

 waves in the open ocean, (2) that they can propagate over substantial distances 

 (350 nautical miles or more in this case), and (3) that the wave directions can 

 be determined with a multielement array and cross-correlation techniques. 



The actual values obtained for wave directions and beam width must be 

 regarded with caution for, in addition to the ambiguity introduced by using 

 only two elements, the values are dependent upon variables that were not well 

 known. The waves were assumed to travel at velocities calculated according to 

 gravity wave formulas applicable in the open ocean. This assumption was prob- 

 ably valid for waves recorded on the thin pack ice, particularly at the long- 

 period end of the spectrum. Waves traveling through the thicker ice of ARLIS 

 II, however, may have velocities different from those assumed, especially at 

 the short-period end of the spectrum. These shorter waves approach the flex- 

 ural waves discussed by Ewing and Crary (193^) and by Hunkins (I962). More 1 

 detailed knowledge of the thickness of ARLIS II, the water depths beneath the j 

 stations and along the wave paths, and the effects of the ARLIS Il-pack ice | 

 boundary would be required for a more accurate analysis. 



The values for the three longest period waves are therefore probably 

 most correct, because they were obtained with the least ambiguity of solutions, 

 are least likely to be affected by refraction and boundary effects of ARLIS II 

 and the pack ice, and are least affected by errors due to recording and digit- 

 izing processes. 



For future experiments, at least three instruments should be used 

 with a spacing of no more than 300 meters on the thinnest pack ice possible 

 and in deep water. It is expected that many of the problems discussed above 

 would be avoided by adhering to these conditions. 



5. SIMULTAKEOUS WAVE AND PRESSURE SPECTRA BEFORE, DURING, AND AFTER A STORM 



a. Introduction 



Since it was clear that some relationship existed between the wind 

 above the ice and the waves beneath, several simultaneous sets of micropressure 

 and wave records were examined. The windspeed and direction graph for Jxily 

 1961 (figure 13) suggested a particularly good time interval between 5 and 6 

 Jiily for such a study. During this interval, the windspeed increased from 12 

 to 25 knots and decreased to 12 knots in the next interval of the same duration. 

 This corresponds to the approach and passing of a storm (figiires 1^ and 15). 

 Five 90-rainute intervals, 5 hours apart, were selected for this analysis. The 

 records are shown in figures 4a, b, and c. 



b. Microbarograph Records 1 



It was assumed that a moving load mechanism similar to the type sug- ! 

 gested by Sytinskiy and Tripol'nikov {196k) was the primary cause of the waves. 

 Thus the microbarograph, which measures directly the oscillatory loading of the 



