European Commission logo
World sea levels

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)
25 Apr 2024 20:59:00
Latency
3703
Level
1.6

Harmonics

Points count
5810447
First date
29 Apr 2011 19:11
Last date
25 Apr 2024 20:59

Click on following link to see data:

Harmonics Constatns
Comp # Period (day) Cos factor (m) Sin factor (m)
0 0.00000 1.13191E+0 0E+0
1 0.12877 8.37807E-5 -1.2473E-5
2 0.12886 2.08512E-4 1.98087E-4
3 0.12938 1.46125E-4 -1.05127E-4
4 0.14707 -1.13983E-4 4.72501E-5
5 0.16841 3.03808E-4 3.15832E-4
6 0.16857 -1.3464E-4 -1.16325E-3
7 0.17036 7.12138E-4 1.44559E-4
8 0.17052 -2.84881E-3 -1.36025E-3
9 0.17251 -1.02488E-3 1.14418E-3
10 0.17470 4.44667E-4 -2.41299E-4
11 0.19989 3.15762E-4 3.75097E-4
12 0.20545 8.11611E-4 -1.15551E-4
13 0.24966 -5.87766E-4 1.45545E-5
14 0.25000 3.50839E-4 3.47029E-4
15 0.25395 -6.67116E-4 -3.98479E-4
16 0.25431 -3.76154E-6 1.15178E-3
17 0.25631 1.05017E-4 -8.76605E-5
18 0.25667 -2.19231E-4 4.2631E-5
19 0.25876 4.82221E-4 -4.83112E-4
20 0.26122 -2.8784E-4 8.6939E-4
21 0.33303 3.12894E-4 1.53346E-3
22 0.34071 1.03319E-3 -1.11845E-4
23 0.34135 6.44021E-4 -4.42421E-4
24 0.34502 -3.26185E-3 3.17736E-3
25 0.34943 -4.29757E-5 3.99903E-4
26 0.48977 -1.54215E-4 9.78736E-4
27 0.49109 1.01293E-3 -1.3061E-4
28 0.49863 1.08755E-2 4.79979E-3
29 0.49932 -9.85222E-4 2.76865E-4
30 0.50000 -3.87003E-2 -4.07835E-2
31 0.50798 1.97012E-3 1.02595E-2
32 0.50924 2.21313E-3 -1.0443E-3
33 0.51606 -4.99014E-3 5.52365E-3
34 0.51679 3.13199E-3 4.49205E-3
35 0.51753 -4.05758E-1 3.07781E-1
36 0.51826 1.54584E-3 -7.25713E-3
37 0.52608 -2.08458E-2 1.5517E-2
38 0.52743 1.02173E-1 6.78686E-2
39 0.53632 1.58604E-2 1.26418E-2
40 0.53772 5.2266E-3 -1.54986E-2
41 0.54697 2.03748E-3 -4.39916E-3
42 0.54843 -1.76027E-3 -4.68146E-4
43 0.89909 6.07161E-5 2.35162E-4
44 0.92942 1.41077E-3 -1.43524E-3
45 0.93417 8.0883E-4 1.7289E-3
46 0.96244 -3.94134E-3 2.79368E-3
47 0.96696 2.18462E-4 -1.61995E-5
48 0.99185 -7.40333E-4 4.56519E-4
49 0.99455 2.13386E-3 7.48654E-4
50 0.99727 4.51881E-2 4.50558E-2
51 1.00000 7.94123E-4 2.14288E-3
52 1.00275 1.09343E-2 1.6068E-2
53 1.00551 -6.26309E-4 1.02091E-3
54 1.02954 -1.29122E-4 2.13447E-3
55 1.03472 1.60183E-3 -2.03645E-3
56 1.04061 3.36877E-4 6.83208E-6
57 1.06951 -7.18293E-4 -1.35129E-3
58 1.07581 3.208E-2 -7.61461E-3
59 1.11346 3.11896E-4 1.40297E-3
60 1.11951 -2.31676E-3 -5.03907E-3
61 1.16035 5.59156E-4 -7.88298E-4
62 1.16693 6.62088E-5 -5.10225E-4
63 1.21136 1.04865E-4 -1.68766E-4
64 13.66079 2.4539E-3 -8.47274E-3
65 14.76529 1.18717E-3 2.0434E-3
66 27.55455 4.40044E-3 1.48476E-2
67 31.81193 -1.9969E-2 2.71749E-3
68 182.62118 -4.78537E-2 5.52194E-2
69 365.25998 6.66393E-2 1.04076E-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

Start
End