height selected on the hour) , and various extreme and/or mean water level 

 statistics were computed. 



Results 



51. Tides at the FRF are semidiurnal with both daily high and low 

 tides approximately equal. Tide height statistics are presented in Table 7. 

 Figure 17 plots the monthly tide statistics for all available data, and 

 Figure 18 compares the distribution of daily high and low water levels and 

 hourly tide heights. The monthly or annual mean sea level (MSL) reported is 

 the average of the hourly heights; whereas, the mean tide level is midway 

 between mean high water (MHW) and mean low water (MLW) which are the averages 

 of the daily high and low water levels, respectively, relative to NGVD. Mean 

 range (MR) is the difference between MHW and MLW levels, and the lowest water 

 level for the month is the extreme low (EL) water while the highest water 

 level is the extreme high (EH) water level. 











Table 7 

















Tide 



Height 



Statistics* 









Month 



Mean 



Mean 



Mean 



Mean 













or 



High 



Tide 



Sea 



Low 



Mean 



Extreme 





Extreme 





Year 

 1987 



Water 



Level 



Level 



Water 



Range 



High 



Date 



Low 



Date 



Jan 



55 



14 



15 



-27 



82 



113 



2 



-62 



24 



Feb 



51 



12 



12 



-27 



78 



82 



17 



-46 



24 



Mar 



60 



20 



20 



-21 



81 



89 



10 



-52 



1 



Apr 

 May 



58 



19 



19 



-20 



78 



99 



26 



-48 



2 



50 



11 



12 



-27 



77 



85 



13 



-51 



13 



Jun 



50 



12 



12 



-27 



77 



83 



24 



-58 



13 



Jul 



54 



15 



15 



-25 



79 



90 



12 



-38 



1 



Aug 



58 



18 



19 



-22 



80 



90 



11 



-57 



10 



Sep 

 Oct 



58 



18 



18 



-22 



80 



88 



20 



-49 



8 



57 



17 



18 



-23 



80 



85 



8 



-59 



5 



Nov 



51 



12 



12 



-27 



78 



93 



11 



-63 



8 



Dec 



- 



- 



- 



Gage Inoperative 



- 



- 



- 



- 



1987 



55 



15 



16 



-24 



79 



113 



Jan 



-63 



Nov 



Prior 



Years 



















1986 



60 



13 



13 



-35 



95 



123 



Dec 



-108 



Jan 



1985 



59 



10 



11 



-37 



96 



136 



Dec 



-93 



Apr 



1984 



64 



16 



16 



-32 



97 



147 



Oct 



-77 



Jul 



1983 



68 



19 



19 



-30 



98 



143 



Jan 



-73 



Mar 



1982 



58 



8 



9 



-42 



99 



127 



Oct 



-108 



Feb 



1981 



59 



8 



9 



-42 



101 



149 



Nov 



-110 



Apr 



1980 



59 



8 



8 



-43 



102 



118 



Mar 



-119 



Mar 



1979 



60 



9 



9 



-43 



103 



121 



Feb 



-95 



Sep 



1979- 





















1987 



60 



12 



12 



-36 



97 



149 



Nov 1981 



-119 



Mar 1980 



Measurements are in centimeters. 



42 



