Peak Spectral Wave Period Distributions 



Annual and monthly peak wave period T p distribution histograms for 1995 

 are presented in Figures D5 and D6. Data for 1980 through 1995 are presented 

 in Figure D7. 



Persistence of Wave Heights 



Table D5 shows the number of times in 1995 when the specified wave 

 height was equaled or exceeded at least once during each day for the duration 

 (consecutive days). Data for 1980 through 1995 are averaged and given in Ta- 

 ble D6. An example is shown below: 



Height 

 m 













Consecutive DavCs) or Lonqer 















1 

 18 



? 

 15 



3 



4 

 14 



5 

 13 



6 7 8 9 10 11 12 13 

 12 11 10 9 



14 

 8 



15 



16 



7 



17 



18 



19+ 



0.5 



1.0 



50 



34 



24 



21 



18 



14 12 8 7 3 2 















1.5 



41 



19 



8 



6 



2 



1 















2.0 



22 



9 



5 



1 



















2.5 



10 



5 



2 





















3.0 



6 



1 























3.5 





1 























4.0 



1 

























This example indicates that wave heights equaled or exceeded 1.0 m 

 50 times for at least 1 day; 34 times for at least 2 days; 24 times for at least 

 3 days, etc. Therefore, on 16 occasions the height equaled or exceeded 1.0 m 

 for 1 day exactly (50 - 34 = 16); on 10 occasions for 2 days; on 3 occasions 

 for 3 days, etc. Note that the height exceeded 1 m 50 times for 1 day or lon- 

 ger, while heights exceeded 0.5 m only 18 times for this same duration. This 

 change in durations occurred because the longer durations of lower waves may 

 be interspersed with shorter, but more frequent, intervals of higher waves. For 

 example, one of the times that the wave heights exceeded 0.5 m for 16 days 

 may have represented three times the height exceeded 1 m for shorter 

 durations. 



Spectra 



Monthly spectra for the offshore staff gauge (Gauge 625) are presented in 

 Figure D8. The plots show "relative" energy density as a function of wave 

 frequency. These figures summarize the large number of spectra for each 



D2 



Appendix D Wave Data for Gauge 625 



