Observations and Measurements of Ocean Waves 



43 



Table 3. Comparison between velocities deducted from observations 

 and computed from wave length and period 



(according to H. Thorade) 



Average 



100±1 100±2 97 groups 



17 to 18 m have been observed and photographed by the stereophotogram- 

 matic method. Gigantic waves of these dimensions seem to occur only in 

 the high Southern latitudes where storms last for a long time without changing 

 their direction. In the North Atlantic the extreme values for waves are about 

 150 m long and from 12 to 13 m high. In exceptional circumstances we find 

 higher waves through interference. Smaller seas and lakes have far smaller 

 waves, as tabulated by Thorade in Table 4. 



Table 4 



In the Southern North Sea 4m. 



Beside the relations between length, velocity and period of the waves, 

 we can establish one for the height of the waves. It can only be applied to 

 waves which have grown to their full development. The influence of the wind 

 on the growth of waves will be dealt with later (see p. 87). The numerous 



