Part 7 



PRELIMINARY ANALYSIS, CHOICE OF GRID SPACING AND 



DISCUSSION OF ALIASING 



Weather and Wave Pole Observations 



Weather and wave pole observations were made prior to and at the time 

 of the flight of the planes. A running graph of the wind direction and velocity 

 and of the estimated significant wave heights and the dominant wave direction 

 as observed on the R. V. ATLANTIS prior to and at the time of the wave pole 

 and stereo observations is shown in figure 7.1, The times of the wave pole 

 observations and of the two pairs of photos finally chosen for a complete 

 analysis are also shown. The winds 6 hours prior to the time of the stereo 

 observations averaged about 19 or 20 knots. 



The significant heights of the uncorrected wave pole observations were 

 computed at WHOI, and the results of these computations yielded the follow- 

 ing values. 



Table 7.1 

 Significant heights from uncorrected wave pole observations 



Time Significant Height 

 1547 to 1610Z 5.02 feet 



1652 to 1715Z 5,04 feet 



1756 to 1821Z 5.12 feet 



A paper by Marks and Chase [1955] summarizes these results and the way 

 the visually observed values seemed to be quite a bithigher than the wave pole 

 values and seemed to remain high for quite a while after the 19 to 20 knot 



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