Greenwich (*t*0) ' local (*t*0) %

(II-5-17)

15

where *S *is the local time meridian (shown on NOS analyses) and the number 15 indicates a time change of

1 hr per 15 deg longitude.

(e) The speed of the time argument (*a*nt in Equation II-5-16) in degrees with respect to time is equal to

the speed of the constituent *a*n multiplied by Equation II-5-17. Therefore, the final relationship between local

and Greenwich phase arguments that account for both differences in location (*-pL*) and local time (*aS*/15) can

be written as:

local (*V*0 % *u*) ' Greenwich (*V*0 % *u*) & *pL*

(II-5-18)

Therefore, a tide at any arbitrary location is computed as

& κn]

(II-5-19)

15

(f) A reconstructed tidal time series of a published NOS harmonic analysis is presented for Sandy Hook,

NJ. The NOS analysis is shown in Figure II-5-12. As can be seen by the reported amplitudes, the *M*2, S2, N2,

generate a 15-day tidal signal beginning on 1 January 1984 at 0000 hr Eastern Standard Time. Computed

values are compared to the high and low tide predictions published in the Tide Tables for 1984 (NOAA 1984)

shown in Figure II-5-13. Because all 37 constituents are not used in the reconstruction, the match is not

perfect; however, it demonstrates the degree of accuracy that can be achieved by using only major

constituents.

II-5-20

Water Levels and Long Waves

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