EM 1110-2-1100 (Part II)
30 Apr 02
Table II-5-3
NOS Tidal Constituents and Arguments
Symbol
Speed, deg/hr
Period, hr
Symbol
Speed, deg/hr
Period, hr
M2
28.984
12.421
Mm
0.544
661.765
S2
30.000
12.000
Ssa
0.082
4390.244
N2
28.439
12.659
Sa
0.041
8780.488
K1
15.041
23.935
Msf
1.015
354.680
M4
57.968
6.2103
Mf
1.098
327.869
O1
13.943
25.819
ρ1
13.471
26.724
M6
86.952
4.140
Q1
13.398
26.870
(MK)3
44.025
8.177
T2
29.958
12.017
S4
60.000
6.000
R2
30.041
11.984
(MN)4
57.423
6.269
(2Q)1
12.854
28.007
ν2
28.512
12.626
P1
14.958
24.067
S6
90.000
4.000
(2SM)2
31.015
11.607
2
27.968
12.872
M3
43.476
8.280
(2N)2
27.895
12.906
L2
29.528
12.192
(OO)1
16.139
22.306
(2MK)3
42.927
8.386
λ2
29.455
12.222
K2
30.082
11.967
S1
15.000
24.000
M8
115.936
3.105
M1
14.496
24.834
(MS)4
58.984
6.103
J1
15.585
23.099
(j) The value κ is approximately constant at every location in the world because it represents the actual
lag between the passing of the tide-producing force (i.e., moon) at a specific location and the following high-
tide contribution of that force at that same location. It is computed as the sum of the theoretical phase or time
lead of the tide-producing force relative to the observer at some fixed time and the measured phase lag ζ from
the observer at that fixed time to the following high water. The theoretical location of the tide-producing force
is referred to as the equilibrium argument (V0 + u). In Figure II-5-10, the tide-producing force and
corresponding equilibrium tide at location M are located (V0 + u) degrees ahead of point T. Conversely, the
equilibrium tide will be located at point T if shifted (V0 + u) degrees. The value of ζ represents the phase lag
from point T to HW.
(k) The equilibrium argument (V0 + u) is computed from equations defining the time-varying relationship
between the earth, moon, and sun. The value of ζ is computed from observed tidal time series data. As
stated, the sum of these two values is approximately constant for any fixed location at any time.
(l) Values of the equilibrium argument for the constituents of Table II-5-3 relative to the passing of the
tidal potential force at the Greenwich meridian for each calendar year from 1850 through 2000 are tabulated
in Schureman (1924). An example is shown in Table II-5-5 for the years 1990 to 2000. Monthly and daily
adjustment tables are also presented. Each of the values is computed according to the respective constituent
speeds shown in Table II-5-3. The equilibrium arguments tabulated in Schureman are referenced to the
meridian of Greenwich; therefore, the argument (V0 + u) represents the phase difference in degrees between
the location of the tidal potential term (moon or sun) and Greenwich relative to some specific time.
II-5-16
Water Levels and Long Waves
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