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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)
09 Feb 2026 00:02:00
Latency
1656
Level
1.49

Harmonics

Points count
6725507
First date
29 Apr 2011 19:11
Last date
09 Feb 2026 00:02

Click on following link to see data:

Harmonics Constatns
Comp # Period (day) Cos factor (m) Sin factor (m)
0 0.00000 1.13026E+0 0E+0
1 0.12877 8.0312E-5 -1.5571E-5
2 0.12886 1.96207E-4 1.52832E-4
3 0.12938 1.46642E-4 -1.10078E-4
4 0.14707 -9.7049E-5 2.6081E-5
5 0.16841 3.31412E-4 3.61435E-4
6 0.16857 -1.6303E-4 -1.09084E-3
7 0.17036 7.40183E-4 1.29871E-4
8 0.17052 -2.76891E-3 -1.33109E-3
9 0.17251 -1.06548E-3 1.12696E-3
10 0.17470 4.1841E-4 -2.69375E-4
11 0.19989 3.00989E-4 3.60133E-4
12 0.20545 7.49022E-4 -7.05874E-5
13 0.24966 -5.09332E-4 -2.19145E-5
14 0.25000 3.02609E-4 2.84148E-4
15 0.25395 -6.01722E-4 -3.95478E-4
16 0.25431 -6.68038E-5 1.06463E-3
17 0.25631 7.27939E-5 -8.0499E-5
18 0.25667 -2.09844E-4 1.01389E-5
19 0.25876 4.26592E-4 -4.69024E-4
20 0.26122 -2.34666E-4 8.25145E-4
21 0.33303 3.20412E-4 1.59966E-3
22 0.34071 1.04166E-3 -9.12867E-5
23 0.34135 5.97676E-4 -4.21758E-4
24 0.34502 -3.22699E-3 3.19284E-3
25 0.34943 5.88652E-5 1.82933E-4
26 0.48977 -7.34334E-5 8.90526E-4
27 0.49109 8.49579E-4 -1.69372E-4
28 0.49863 1.18841E-2 4.98802E-3
29 0.49932 -9.29671E-4 2.29906E-4
30 0.50000 -3.89392E-2 -4.09034E-2
31 0.50798 2.60858E-3 1.01542E-2
32 0.50924 2.15005E-3 -1.02336E-3
33 0.51606 -4.41828E-3 4.55903E-3
34 0.51679 2.52698E-3 4.12147E-3
35 0.51753 -4.02952E-1 3.06877E-1
36 0.51826 1.76975E-3 -6.52826E-3
37 0.52608 -2.0684E-2 1.50282E-2
38 0.52743 1.02371E-1 6.80371E-2
39 0.53632 1.55703E-2 1.25854E-2
40 0.53772 5.36879E-3 -1.55417E-2
41 0.54697 2.11189E-3 -4.3644E-3
42 0.54843 -1.75543E-3 -5.12769E-4
43 0.89909 9.56958E-5 2.49358E-4
44 0.92942 1.54148E-3 -1.61367E-3
45 0.93417 7.48252E-4 1.61922E-3
46 0.96244 -3.91281E-3 2.92733E-3
47 0.96696 3.03135E-4 2.56842E-5
48 0.99185 -5.47608E-4 4.28887E-4
49 0.99455 1.95111E-3 4.10716E-4
50 0.99727 4.65586E-2 4.56777E-2
51 1.00000 6.4354E-4 2.13296E-3
52 1.00275 1.10875E-2 1.61307E-2
53 1.00551 -3.86972E-4 8.75542E-4
54 1.02954 -9.65844E-5 1.90993E-3
55 1.03472 1.88711E-3 -1.99479E-3
56 1.04061 2.3489E-4 7.31491E-5
57 1.06951 -5.81555E-4 -1.128E-3
58 1.07581 3.33737E-2 -7.59166E-3
59 1.11346 3.04766E-4 1.20298E-3
60 1.11951 -2.22858E-3 -5.28903E-3
61 1.16035 5.09874E-4 -6.90056E-4
62 1.16693 -3.07643E-5 -3.48724E-4
63 1.21136 9.4628E-5 -1.59815E-4
64 13.66079 1.76497E-3 -8.96978E-3
65 14.76529 1.39233E-3 2.38318E-3
66 27.55455 3.89129E-3 1.32496E-2
67 31.81193 -1.68278E-2 2.63258E-3
68 182.62118 -4.41672E-2 4.90981E-2
69 365.25998 6.19746E-2 9.96914E-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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