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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)
17 Jul 2025 02:56:00
Latency
519
Level
0.83

Harmonics

Points count
6437716
First date
29 Apr 2011 19:11
Last date
17 Jul 2025 01:02

Click on following link to see data:

Harmonics Constatns
Comp # Period (day) Cos factor (m) Sin factor (m)
0 0.00000 1.1316E+0 0E+0
1 0.12877 7.6594E-5 -1.64027E-5
2 0.12886 1.95466E-4 1.65878E-4
3 0.12938 1.45231E-4 -1.07573E-4
4 0.14707 -1.14267E-4 3.47406E-5
5 0.16841 3.30477E-4 3.44826E-4
6 0.16857 -1.56123E-4 -1.11005E-3
7 0.17036 7.20717E-4 1.26873E-4
8 0.17052 -2.79261E-3 -1.3242E-3
9 0.17251 -1.05472E-3 1.14511E-3
10 0.17470 4.27113E-4 -2.55227E-4
11 0.19989 3.47342E-4 3.6936E-4
12 0.20545 7.80079E-4 -1.02222E-4
13 0.24966 -5.13198E-4 -2.47898E-5
14 0.25000 3.21995E-4 3.10069E-4
15 0.25395 -6.16922E-4 -3.84941E-4
16 0.25431 -1.8429E-5 1.07922E-3
17 0.25631 9.76667E-5 -7.87052E-5
18 0.25667 -2.32476E-4 2.19459E-5
19 0.25876 4.52927E-4 -4.69921E-4
20 0.26122 -2.46705E-4 8.3444E-4
21 0.33303 3.14484E-4 1.55869E-3
22 0.34071 1.05511E-3 -9.71571E-5
23 0.34135 6.21191E-4 -4.2466E-4
24 0.34502 -3.23508E-3 3.17227E-3
25 0.34943 4.32926E-5 2.3761E-4
26 0.48977 -8.50202E-5 8.96304E-4
27 0.49109 8.94615E-4 -1.78903E-4
28 0.49863 1.15657E-2 5.0498E-3
29 0.49932 -9.53206E-4 8.52292E-5
30 0.50000 -3.88411E-2 -4.07535E-2
31 0.50798 2.43811E-3 1.01938E-2
32 0.50924 2.14816E-3 -9.91166E-4
33 0.51606 -4.54523E-3 4.59419E-3
34 0.51679 2.30967E-3 4.58744E-3
35 0.51753 -4.0394E-1 3.07048E-1
36 0.51826 1.32171E-3 -7.12268E-3
37 0.52608 -2.06504E-2 1.51759E-2
38 0.52743 1.02398E-1 6.78618E-2
39 0.53632 1.56089E-2 1.25608E-2
40 0.53772 5.32371E-3 -1.55163E-2
41 0.54697 2.07888E-3 -4.38132E-3
42 0.54843 -1.75325E-3 -5.03512E-4
43 0.89909 8.91882E-5 2.80148E-4
44 0.92942 1.51545E-3 -1.56323E-3
45 0.93417 7.62035E-4 1.70271E-3
46 0.96244 -3.91833E-3 2.85829E-3
47 0.96696 3.00294E-4 4.6651E-5
48 0.99185 -5.38216E-4 4.15626E-4
49 0.99455 1.82879E-3 6.54254E-4
50 0.99727 4.61426E-2 4.56318E-2
51 1.00000 6.10326E-4 1.95116E-3
52 1.00275 1.10537E-2 1.62585E-2
53 1.00551 -5.07547E-4 9.23504E-4
54 1.02954 -5.32504E-5 1.91917E-3
55 1.03472 1.81825E-3 -2.0005E-3
56 1.04061 3.11952E-4 8.56794E-5
57 1.06951 -6.06215E-4 -1.25461E-3
58 1.07581 3.29972E-2 -7.64246E-3
59 1.11346 3.05777E-4 1.23407E-3
60 1.11951 -2.22688E-3 -5.1722E-3
61 1.16035 4.91544E-4 -7.29706E-4
62 1.16693 1.15202E-6 -4.44112E-4
63 1.21136 9.91942E-5 -2.15192E-4
64 13.66079 2.02056E-3 -8.97691E-3
65 14.76529 1.22889E-3 2.20552E-3
66 27.55455 3.6857E-3 1.34209E-2
67 31.81193 -1.74284E-2 2.37568E-3
68 182.62118 -4.3706E-2 5.16044E-2
69 365.25998 6.20539E-2 9.91569E-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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