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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)
03 Nov 2026 15:59:00
Latency
2551
Level
1.26

Harmonics

Points count
7096569
First date
29 Apr 2011 19:11
Last date
03 Nov 2026 15:59

Click on following link to see data:

Harmonics Constatns
Comp # Period (day) Cos factor (m) Sin factor (m)
0 0.00000 1.12517E+0 0E+0
1 0.12877 8.18933E-5 -6.95368E-6
2 0.12886 1.93817E-4 1.48243E-4
3 0.12938 1.55315E-4 -1.20747E-4
4 0.14707 -9.46312E-5 1.93903E-5
5 0.16841 3.24451E-4 3.72039E-4
6 0.16857 -1.58839E-4 -1.0583E-3
7 0.17036 7.28746E-4 9.87757E-5
8 0.17052 -2.74831E-3 -1.29924E-3
9 0.17251 -1.04975E-3 1.11776E-3
10 0.17470 4.12817E-4 -2.9289E-4
11 0.19989 3.02016E-4 3.71618E-4
12 0.20545 7.01887E-4 -8.80407E-5
13 0.24966 -4.50091E-4 -8.17948E-5
14 0.25000 2.15637E-4 2.98565E-4
15 0.25395 -5.12486E-4 -3.81251E-4
16 0.25431 -9.63346E-5 9.89064E-4
17 0.25631 8.22471E-5 -8.92893E-5
18 0.25667 -1.91909E-4 -9.81013E-6
19 0.25876 3.93299E-4 -4.79869E-4
20 0.26122 -2.12339E-4 7.85668E-4
21 0.33303 3.5102E-4 1.603E-3
22 0.34071 1.02114E-3 -6.224E-5
23 0.34135 5.69216E-4 -4.36166E-4
24 0.34502 -3.19071E-3 3.20204E-3
25 0.34943 5.91723E-5 1.00567E-4
26 0.48977 -9.66199E-5 9.27728E-4
27 0.49109 8.40145E-4 -1.78526E-4
28 0.49863 1.21442E-2 4.90702E-3
29 0.49932 -9.77913E-4 1.66952E-4
30 0.50000 -3.89148E-2 -4.08889E-2
31 0.50798 2.84018E-3 9.97213E-3
32 0.50924 2.24944E-3 -1.01077E-3
33 0.51606 -4.36955E-3 4.3425E-3
34 0.51679 2.10094E-3 4.07349E-3
35 0.51753 -4.02181E-1 3.06964E-1
36 0.51826 1.57663E-3 -6.40764E-3
37 0.52608 -2.05168E-2 1.49275E-2
38 0.52743 1.02351E-1 6.82102E-2
39 0.53632 1.54354E-2 1.26012E-2
40 0.53772 5.33041E-3 -1.56155E-2
41 0.54697 2.11513E-3 -4.34084E-3
42 0.54843 -1.75322E-3 -5.02864E-4
43 0.89909 8.97548E-5 2.31559E-4
44 0.92942 1.54878E-3 -1.643E-3
45 0.93417 6.996E-4 1.62061E-3
46 0.96244 -3.88948E-3 2.94315E-3
47 0.96696 4.08629E-4 7.2294E-5
48 0.99185 -5.67236E-4 4.60989E-4
49 0.99455 1.64883E-3 3.717E-4
50 0.99727 4.71078E-2 4.57122E-2
51 1.00000 4.98396E-4 2.16475E-3
52 1.00275 1.09614E-2 1.60815E-2
53 1.00551 -3.36461E-4 8.71297E-4
54 1.02954 -9.48593E-5 1.80898E-3
55 1.03472 1.87281E-3 -1.97539E-3
56 1.04061 2.4604E-4 1.35299E-4
57 1.06951 -6.50698E-4 -1.06959E-3
58 1.07581 3.39065E-2 -7.39071E-3
59 1.11346 3.66674E-4 1.09141E-3
60 1.11951 -2.14212E-3 -5.34847E-3
61 1.16035 5.00583E-4 -7.14326E-4
62 1.16693 -6.2536E-5 -3.13698E-4
63 1.21136 1.6516E-4 -2.19598E-4
64 13.66079 1.27225E-3 -8.73198E-3
65 14.76529 1.15279E-3 2.17997E-3
66 27.55455 2.80693E-3 1.2641E-2
67 31.81193 -1.64591E-2 1.73933E-3
68 182.62118 -4.07348E-2 4.5844E-2
69 365.25998 6.2725E-2 9.67736E-2
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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