Waves 



71. This section presents summaries of the wave data. A review of the 



wave conditions during 1984 and a comparison to previous years are followed by 



a discussion of the wave climate for 1980 through 1984. Appendix B contains 



summaries for each gage which include height and period distributions, wave 



direction distributions, persistence tables and wave spectra for gage 625 



during storm conditions. A discussion of individual major storms is given in 



Part VI, and Appendix D contains hourly wave data for times when the heights 



H exceeded 2 m at the seaward end of the FRF pier. 

 m 

 o 



Present data year 



72. Spatial variation. The distribution of wave heights for all three 

 gages operated during the year is shown in Figure 10. For a given frequency 

 of occurrence, wave heights were highest at the gage located 3 km from shore 

 (gage 620), second at the pier end (gage 625), and lowest at the landward end 

 of the pier (gage 615). This pattern of variation (decrease of wave height 

 with depth) is consistent with previous years' data. Refraction, bottom fric- 

 tion, and wave breaking contribute to the observed differences in height. 

 Wave height statistics for the staff gage (615) located at the landward end of 

 the pier in shallow water were considerably different than the other gages. 



In all but the very calmest conditions, this gage is within the breaker zone. 

 Consequently, these statistics represent a lower energy wave climate in which 

 the annual mean height is more than 20 percent less than at the seaward end of 

 the pier. 



73. The distributions of wave periods for all of the gages are shown in 

 Figure 11. Although the distributions of wave periods for gages 625 and 620 

 were similar, there was a tendency for gage 625 to have higher frequencies of 

 wave periods longer than 9 sec and fewer wave periods shorter than 9 sec. 

 Gage 615 had a higher occurrence of wave periods 6 sec and less, primarily 

 caused by waves that frequently break seaward of the gage,. This pattern of 

 variation between gages is consistent with data from the previous years. 



74. Temporal variation. Temporal height and period trends for gage 625 

 and 620 are shown in Figures 12 and 13, respectively, and are consistent with 

 those for gage 615. Seasonal wave height distribution variations as shown for 



39 



