The frequency value of different wave intensities (up to 3 meters in 

 height) which have been recorded in the Baltic and North Seas has shown 

 that a frequency distribution of wave heights and lengths characterizing 

 the waves can be set up with the evaluation of 300 of the highest 800 waves 

 according to the height of the waves from which can be selected the class 

 distribution for the frequency value „ 



For the evaluation, a form sheet has been set up (figure 1) which per- 

 mits a quick and easy tabulation of the successively evaluated waves and 

 in which, by simple addition of the numerical values, the frequency distri- 

 bution of the first and second kind can be determined for wave heights and 

 lengths. With sufficient accuracy the frequency distribution for the steep- 

 ness h/L can be determined with the aid of the form sheet in the more pre- 

 dominant classes o 



The procedure of a frequency valuation (4) follows; From a given wave 

 condition, waves are taken which, according to their properties or measure- 

 ments, will be assigned to definite classes (of equal size),, The occurrence 

 of the waves in a single class interval, expressed through a number, H}_, 

 makes a frequency of the first kind, representing the class average „ The 

 sum of all the investigated waves is the total frequency No By addition, 

 one obtains the frequency of the second group (H2) from the frequency of 

 the first kind (H^) The frequency of the second group indicates how often 

 a class limit will be exceeded or how many values will be below a class limit 

 when the characteristics are considered the class average,, With a sufficient 

 number of observations;, the frequency of the second kind (cumulative frequency) 

 may be produced in the form of a curve (summation curve) „ The preparation 

 of a frequency distribution as a summation curve has the advantage that the 

 collections which have been evaluated with different class distributions, 

 may be compared with one another, since the class limit is worked out only 

 from the number of determined points for the curve, in which process the 

 principles are not changed „ To make the frequency distribution independent 

 of the time or the extent of the valuation, one specifies the frequency in 

 percentage (percent frequency) o 



The cumulative frequency of wave steepness (H/L) for the data given 

 and analyzed as in figure 1 resulted in the following s 



H/L % Hg E 2 % 



1/1- 



1/10 



77 



1/10 • 



- 1/20 



161 



1/20 - 



- 1/30 



261 



1/30 ■ 



- 1/40 



85 



1/40 ■ 



- 1/50 



36 



1/50 • 



- 1/60 



31 



1/60 ■ 



- 1/70 



5 



1/70 ■ 



- 1/80- 



26 



1/80 ■ 



- 1/90 



3 



77 



14 c2 



238 



34.6 



499 



72 o5 



584 



84 o9 



620 



90 cl 



651 



94 06 



656 



95»3 



682 



99=1 



685 



99o5» 



31 



