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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)
02 Apr 2025 06:59:00
Latency
7360
Level
1.08

Harmonics

Points count
6289489
First date
29 Apr 2011 19:11
Last date
02 Apr 2025 06:59

Click on following link to see data:

Harmonics Constatns
Comp # Period (day) Cos factor (m) Sin factor (m)
0 0.00000 1.13231E+0 0E+0
1 0.12877 8.16619E-5 -1.16761E-5
2 0.12886 2.0184E-4 1.68167E-4
3 0.12938 1.46454E-4 -1.02678E-4
4 0.14707 -1.17369E-4 3.36348E-5
5 0.16841 3.17844E-4 3.29824E-4
6 0.16857 -1.53292E-4 -1.11762E-3
7 0.17036 7.20199E-4 1.30002E-4
8 0.17052 -2.79879E-3 -1.31617E-3
9 0.17251 -1.04764E-3 1.13765E-3
10 0.17470 4.33713E-4 -2.5783E-4
11 0.19989 3.26456E-4 3.51441E-4
12 0.20545 7.96209E-4 -9.80409E-5
13 0.24966 -5.37918E-4 -1.61811E-5
14 0.25000 3.23003E-4 3.00467E-4
15 0.25395 -6.35293E-4 -3.87509E-4
16 0.25431 -1.02886E-5 1.08379E-3
17 0.25631 9.63785E-5 -7.19137E-5
18 0.25667 -2.27136E-4 2.07507E-5
19 0.25876 4.4868E-4 -4.7959E-4
20 0.26122 -2.48448E-4 8.32288E-4
21 0.33303 2.83427E-4 1.5516E-3
22 0.34071 1.04799E-3 -1.18771E-4
23 0.34135 6.2116E-4 -4.2927E-4
24 0.34502 -3.25015E-3 3.1706E-3
25 0.34943 3.5502E-5 2.82049E-4
26 0.48977 -8.06166E-5 9.31975E-4
27 0.49109 9.01163E-4 -1.75559E-4
28 0.49863 1.14344E-2 4.9931E-3
29 0.49932 -8.88956E-4 1.96855E-4
30 0.50000 -3.88341E-2 -4.08414E-2
31 0.50798 2.35112E-3 1.02556E-2
32 0.50924 2.21559E-3 -1.04772E-3
33 0.51606 -4.72005E-3 4.83505E-3
34 0.51679 2.75134E-3 4.41809E-3
35 0.51753 -4.0444E-1 3.06913E-1
36 0.51826 1.57751E-3 -6.79882E-3
37 0.52608 -2.07105E-2 1.52843E-2
38 0.52743 1.02389E-1 6.78521E-2
39 0.53632 1.5684E-2 1.26091E-2
40 0.53772 5.28779E-3 -1.55849E-2
41 0.54697 2.07109E-3 -4.36611E-3
42 0.54843 -1.77105E-3 -4.90816E-4
43 0.89909 9.24206E-5 2.63932E-4
44 0.92942 1.49461E-3 -1.57526E-3
45 0.93417 7.5337E-4 1.70448E-3
46 0.96244 -3.8862E-3 2.89633E-3
47 0.96696 3.22455E-4 -8.87698E-6
48 0.99185 -6.45268E-4 5.31539E-4
49 0.99455 2.04908E-3 5.87097E-4
50 0.99727 4.59091E-2 4.5558E-2
51 1.00000 7.3534E-4 2.10374E-3
52 1.00275 1.10265E-2 1.61506E-2
53 1.00551 -5.03584E-4 9.64893E-4
54 1.02954 -7.42495E-5 1.96454E-3
55 1.03472 1.7607E-3 -2.04539E-3
56 1.04061 3.30664E-4 -4.36041E-6
57 1.06951 -6.45245E-4 -1.17946E-3
58 1.07581 3.28112E-2 -7.67198E-3
59 1.11346 3.08264E-4 1.25359E-3
60 1.11951 -2.25331E-3 -5.2001E-3
61 1.16035 5.03193E-4 -6.89197E-4
62 1.16693 1.20321E-5 -4.77883E-4
63 1.21136 1.0838E-4 -2.06457E-4
64 13.66079 2.15539E-3 -8.71199E-3
65 14.76529 1.06884E-3 2.09485E-3
66 27.55455 3.73034E-3 1.36339E-2
67 31.81193 -1.79362E-2 2.70929E-3
68 182.62118 -4.52369E-2 5.0502E-2
69 365.25998 6.1831E-2 1.00788E-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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