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

 tistics were computed. 



Results 



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

 approximately equal. Tide height statistics are presented in Table 16. Fig- 

 ure 28 plots the monthly tide statistics for all available data, and Figure 29 

 compares the distribution of daily high and low water levels and hourly tide 

 heights. The monthly or annual mean sea level reported is the average of the 

 hourly heights, while the mean tide level is midway between mean high water 

 and mean low water which are the averages of the daily high and low water 

 levels, respectively, relative to NGVD. Mean range is the difference between 

 mean high and low water levels, and the lowest water level for the month is 

 the extreme low water while the highest water level is the extreme high water 

 level. 



Table 16 

 Tide Height Statistics* 























Month 



Mean 



Mean 



Mean 



Mean 













or 



High 



Tide 



Sea 



Low 



Mean 



Extreme 





Extreme 





Year 

 I5S5 

 Jan 



Water 



Level 



Level 



Water 



Range 



High 



Date 



Low 



Date 



41 



-7 



-7 



-55 



96 



99 



11 



-108 



10 



Feb 



65 



16 



16 



-32 



96 



107 



25 



-59 



10 



Mar 



45 



-4 



-3 



-52 



97 



81 



1 



-96 



9 



Apr 



69 



21 



21 



-28 



97 



117 



24 



-48 



25 



May 



62 



14 



14 



-34 



96 



114 



9 



-71 



5 



Jun 



52 



4 



4 



-44 



94 



99 



22 



-78 



19 



Jul 



61 



14 



14 



-32 



93 



106 



20 



-48 



26 



Aug 



64 



17 



18 



-29 



93 



117 



18 



-63 



11 



Sep 



64 



17 



17 



-30 



94 



92 



4 



-66 



19 



Oct 



73 



26 



26 



-22 



95 



112 



10 



-46 



5 



Nov 



67 



19 



19 



-29 



96 



106 



6 



-54 



2, 29 



Dec 



63 



15 



16 



-34 



97 



123 



2 



-70 



5 



1986 



60 



13 



13 



-35 



95 



123 



Dec 



-108 



Jan 



Prior 



Years 



















1965 



59 



10 



11 



-37 



96 



136 



Dec 



-93 



Apr 



1964 



64 



16 



16 



-32 



97 



147 



Oct 



-77 



Jul 



1963 



68 



19 



19 



-30 



98 



143 



Jan 



-73 



Mar 



1962 



58 



8 



9 



-42 



99 



127 



Oct 



-108 



Feb 



1961 



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- 



61 



11 



12 



-38 



99 



149 



Nov 1981 



-119 



Mar 1980 



1986 





















* Measurements are in centimetres, 



60 



