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Tide Gauge Details - Tonga Island - Nukualofa_TO

Device description

Name
Tonga Island - Nukualofa_TO
Country
Tonga Island
Group
TD UNESCO
Lat/Lon
-21.136801 / -175.180695

Last measured values

Time(UTC)
12 Jan 2026 22:02:00
Latency
1463
Level
0.97

Harmonics

Points count
6687038
First date
29 Apr 2011 19:11
Last date
12 Jan 2026 22:02

Click on following link to see data:

Harmonics Constatns
Comp # Period (day) Cos factor (m) Sin factor (m)
0 0.00000 1.13066E+0 0E+0
1 0.12877 7.84561E-5 -1.41662E-5
2 0.12886 1.97152E-4 1.55963E-4
3 0.12938 1.46311E-4 -1.09943E-4
4 0.14707 -9.50998E-5 2.89345E-5
5 0.16841 3.32299E-4 3.58195E-4
6 0.16857 -1.6521E-4 -1.09345E-3
7 0.17036 7.35048E-4 1.20509E-4
8 0.17052 -2.77867E-3 -1.331E-3
9 0.17251 -1.06113E-3 1.13011E-3
10 0.17470 4.16985E-4 -2.70259E-4
11 0.19989 2.9907E-4 3.72923E-4
12 0.20545 7.48901E-4 -8.28871E-5
13 0.24966 -5.08091E-4 -1.32967E-5
14 0.25000 3.04691E-4 2.89242E-4
15 0.25395 -6.13584E-4 -3.80711E-4
16 0.25431 -5.96201E-5 1.08398E-3
17 0.25631 7.39044E-5 -8.46707E-5
18 0.25667 -2.17864E-4 1.01062E-5
19 0.25876 4.28756E-4 -4.8082E-4
20 0.26122 -2.38585E-4 8.26005E-4
21 0.33303 3.41281E-4 1.58518E-3
22 0.34071 1.04698E-3 -8.22976E-5
23 0.34135 6.10919E-4 -4.22351E-4
24 0.34502 -3.23049E-3 3.19191E-3
25 0.34943 5.38536E-5 1.86956E-4
26 0.48977 -6.57338E-5 8.81283E-4
27 0.49109 8.30537E-4 -1.70901E-4
28 0.49863 1.18328E-2 5.01749E-3
29 0.49932 -9.54145E-4 2.77927E-4
30 0.50000 -3.89413E-2 -4.08592E-2
31 0.50798 2.57969E-3 1.01751E-2
32 0.50924 2.16087E-3 -1.06133E-3
33 0.51606 -4.47882E-3 4.48182E-3
34 0.51679 2.43462E-3 4.07808E-3
35 0.51753 -4.03057E-1 3.06873E-1
36 0.51826 1.66887E-3 -6.49279E-3
37 0.52608 -2.06636E-2 1.50467E-2
38 0.52743 1.02359E-1 6.80289E-2
39 0.53632 1.55569E-2 1.25994E-2
40 0.53772 5.36723E-3 -1.5551E-2
41 0.54697 2.11182E-3 -4.38271E-3
42 0.54843 -1.74579E-3 -5.05323E-4
43 0.89909 9.45296E-5 2.62289E-4
44 0.92942 1.53404E-3 -1.60293E-3
45 0.93417 7.50015E-4 1.633E-3
46 0.96244 -3.93495E-3 2.92251E-3
47 0.96696 3.18975E-4 4.99221E-6
48 0.99185 -5.74191E-4 3.92432E-4
49 0.99455 1.90932E-3 3.86617E-4
50 0.99727 4.65071E-2 4.5669E-2
51 1.00000 5.88798E-4 2.14538E-3
52 1.00275 1.10421E-2 1.61669E-2
53 1.00551 -4.15002E-4 9.29277E-4
54 1.02954 -5.83181E-5 1.91303E-3
55 1.03472 1.87448E-3 -1.96989E-3
56 1.04061 2.53197E-4 8.54831E-5
57 1.06951 -6.09221E-4 -1.16361E-3
58 1.07581 3.33254E-2 -7.59732E-3
59 1.11346 3.26523E-4 1.20921E-3
60 1.11951 -2.23148E-3 -5.27954E-3
61 1.16035 4.72118E-4 -6.81499E-4
62 1.16693 -1.87705E-5 -3.73217E-4
63 1.21136 8.91273E-5 -1.89076E-4
64 13.66079 1.71325E-3 -9.13863E-3
65 14.76529 1.20986E-3 2.41425E-3
66 27.55455 3.72577E-3 1.32893E-2
67 31.81193 -1.68737E-2 2.39829E-3
68 182.62118 -4.38374E-2 4.97937E-2
69 365.25998 6.26688E-2 1.00083E-1
Mathematical Formula
Tide calculation mathematical formula
Visual Basic Syntax
Function EstimateTideValues() As [Function]
                        Dim Pi As [Double] = Math.PI
                        Dim sum As [Double] = harmonics(0, 1)
                        For k As Int16 = 1 To harmonics.GetUpperBound(0)
                        Dim period As [Double] = 2 * Pi / harmonics(k, 0)
                        Dim coefCos As [Double] = harmonics(k, 1)
                        Dim coefSin As [Double] = harmonics(k, 2) 
                        sum = sum + coefCos * Math.Cos(time * period)
                        sum = sum + coefSin * Math.Sin(time * period)
                        Next
                        Return sum
                        End Function
C# Syntax
double EstimateTideValues()
                        {
                        double Pi = Math.PI;
                        double sum = harmonics[0, 1];
                        for (int k=1; k <= harmonics.GetUpperBound(0); k++)
                        {
                        double period = 2 * Pi / harmonics[k, 0];
                        double coefCos = harmonics[k, 1];
                        double coefSin = harmonics[k, 2];
                        sum += coefCos * Math.Cos(time * period);
                        sum += coefSin * Math.Sin(time * period);
                        }
                        return sum;
                        }

Axis ranges

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