longer periods, the tendency is for the directions to scatter about shore nor- 

 mal. Periods of swell and well-developed wind seas overlap in this region. 

 In this figure, both period and direction are discretely defined so that one 

 symbol may represent more than one observation. This makes the distribution 

 appear more uniform than indicated by Figure 11, which shows the true dis- 

 tribution. 



188. The parameters H^g and Tpjpg can be combined indirectly to 

 make a dimensionless parameter known as bulk wave steepness. Using fp,iFs 

 from the frequency spectrum in Equation 2 yields the corresponding wavelength 

 Lp IFS • The ratio U^^/l^ j^s defines bulk wave steepness. The correlation of 

 this with peak direction ^p.ios ^^ shown in Figure 15. Though there is 

 significant scatter, the climatology is consistent with previous discussion. 

 Long, low waves (low steepness) tend to center on shore-normal with some 

 contributions from the southeast quadrant (negative angles). High- steepness 

 waves, associated with energetic seas, tend to be distributed through the 

 northeast quadrant (positive angles) . 





1 1 1 1 1 i 



o 





1 





. 









o 











o 



o 







' 





a o 



^00 «^j o o 



o 8 ooSbo o^ 



o 











o 





















o8" ^ oo 



% 



<p 



o 





- 





eg o 







- 



o°o'? 0,0^^ 



cr-Q 



p 



o 



- 





S^'^o 







^ 



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o 9 i 



j 





D&ftg 



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i 



o o8 o 

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1 . , 1 . . 



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1 



f 1 1 , 





90,0 60.0 30.0 0.0 -30.0 -60.0 -90.0 



^p.iDs (deg) 



Figure 15. Correlation of peak direction with 



bulk steepness 



75 



