periods arriving "before the short periods. No attempt was made to estimate 

 the point of origin of these waves by relating their group velocities and 

 times of arrival as Munk et al. (1963) had done, because the sources were 

 too close and too wid? to assume a point source origin necessary for such 

 calculations. 



The moving-load-resonant-plate theory of Sytinskiy and Tripol'nikov 

 could not be adequately tested, because the range of periods that they 

 associated with a water depth of 150m (12 to 15 seconds) is masked by the 

 natural free oscillation of ARLIS II. It appears, however, that there is 

 sufficient energy in the micropressure waves alone to cause water waves 

 having these periods simply by sympathetic vibration. 



The work discussed so far suggests several further investigations 

 both in the Arctic Ocean Basin and in the open ocean. A tripartite gravi- 

 meter array, approximately 300 meters on a side, should be established on 

 pack ice in deep water somewhere in the central Arctic Ocean Basin. At each 

 station there should also be a microbarograph and provision for recording 

 surface wind velocity continuously. The gravimeter and microbarograph data 

 should be recorded digitally in a form that could be fed directly into a 

 computer. Analog output alone should not be considered owing to the immense 

 task involved in converting it to digital form. If gravimeter recordings 

 are continuous, waves generated anywhere in the Arctic Ocean Basin would be 

 recorded. Their sources could also be determined. 



Similarly, the three-dimensionality and propagation characteristics 

 of the micropressure waves could be studied with the microbarograph array. 

 Finally, cross-correlations between the two phenomena should be useful in 

 determining quantitatively air-sea energy transfer relationships as a function 

 of wave period. Many of these findings wotild probably apply to the open ocean 

 as well. 



Such a study could provide statistical information on wave directions 

 and might provide information on ice breakup due especially to what Assur 

 (1963) calls "long-wave cracks". 



Since the micropressure waves described here have been observed 

 elsewhere, it is probable that they would be observed over the open ocean 

 also. A station might very profitably be established on a stable platform 

 such as ARGUS ISLAND near Bermuda. 



ACOJOVJLEDGEI'ENTS 



This study was a special project jointly supported by the U.S. Naval 

 Oceanographic Office and the Office of Naval Research. The Oceanographic 

 Office provided the LaCoste-Romberg gravimeter and supported the data reduc- 

 tion. The Office of Naval Research provided logistic support throxogh its 

 Arctic Research Laboratory at Barrow, Alaska. The Geophysical and Polar 

 Research Center, University of Wisconsin, provided the World-Wide gravimeter. 

 The T-21 microbarograph was generously loaned by the Terrestrial Sciences 

 Laboratory of the Air Force Cambridge Research Laboratories. 



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