THE STATE OF THE SEA 



The preceding discussion has dealt only with long-crested 

 waves, that is, waves with very long crests and troughs. Waves 

 may also have wave-shaped crests and troughs. In the presence 

 of such short-crested waves the free water surface shows a ser- 

 ies of alternating "highs" and "lows" (page 10). Furtheriaore , 

 attention has been paid only to the waves which accumulate the 

 largest amount of energy and attain the greatest heights and 

 longest periods. In addition to these waves, and superimposed 

 upon them, a large variety of shorter and lower waves will also 

 be present. At wind velocities exceeding Beaufort 3 many of 

 these shorter waves increase so rapidly in height that they break, 

 forming white caps . It appears that at -low wind velocities a 

 great amount of energy goes into the formation of regular long- 

 crested waves, while at high wind velocities a large part is 

 used in the generation of small and short-crested waves. 



After the 'waves leave the generating area, the small waves 

 and the short-crested waves die out quickly because they contain 

 little energy, and the long-crested waves of maximum height, which 

 have been dealt with in the preceding analysis, are responsible 

 for the emerging swell . In the generating area, however, the brok- 

 en appearance of the sea surface is chiefly determined by the pres- 

 ence of the small, short-crested waves and is described by the term 

 "state of the sea." 



For the state of the sea there have been proposed several 

 scales of which the Douglas Sea Scale is the most widely used. 



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