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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)
27 Jul 2026 04:53:00
Latency
3965
Level
1.26

Harmonics

Points count
6963251
First date
29 Apr 2011 19:11
Last date
27 Jul 2026 04:53

Click on following link to see data:

Harmonics Constatns
Comp # Period (day) Cos factor (m) Sin factor (m)
0 0.00000 1.12657E+0 0E+0
1 0.12877 8.88106E-5 -6.08889E-6
2 0.12886 1.92054E-4 1.49896E-4
3 0.12938 1.50596E-4 -1.24339E-4
4 0.14707 -9.29774E-5 2.28699E-5
5 0.16841 3.25023E-4 3.7722E-4
6 0.16857 -1.56238E-4 -1.08197E-3
7 0.17036 7.421E-4 1.22173E-4
8 0.17052 -2.75086E-3 -1.32942E-3
9 0.17251 -1.06359E-3 1.1182E-3
10 0.17470 4.0991E-4 -2.86908E-4
11 0.19989 3.43818E-4 3.81505E-4
12 0.20545 7.19129E-4 -8.67669E-5
13 0.24966 -4.61138E-4 -5.09671E-5
14 0.25000 2.61895E-4 2.8639E-4
15 0.25395 -5.57822E-4 -3.92536E-4
16 0.25431 -8.56018E-5 1.03798E-3
17 0.25631 6.34915E-5 -8.60871E-5
18 0.25667 -1.95656E-4 -4.70259E-6
19 0.25876 4.09048E-4 -4.74946E-4
20 0.26122 -2.19163E-4 8.07671E-4
21 0.33303 3.60748E-4 1.5993E-3
22 0.34071 1.02737E-3 -6.90084E-5
23 0.34135 5.68927E-4 -4.35855E-4
24 0.34502 -3.20698E-3 3.20765E-3
25 0.34943 6.36703E-5 1.43127E-4
26 0.48977 -7.95902E-5 8.87864E-4
27 0.49109 7.98876E-4 -1.76016E-4
28 0.49863 1.21425E-2 4.94235E-3
29 0.49932 -1.02829E-3 1.51456E-4
30 0.50000 -3.88801E-2 -4.09424E-2
31 0.50798 2.73451E-3 1.00652E-2
32 0.50924 2.16826E-3 -1.07233E-3
33 0.51606 -4.19609E-3 4.32698E-3
34 0.51679 2.13651E-3 4.3345E-3
35 0.51753 -4.02493E-1 3.0696E-1
36 0.51826 1.64163E-3 -6.69271E-3
37 0.52608 -2.05598E-2 1.49199E-2
38 0.52743 1.02368E-1 6.81168E-2
39 0.53632 1.5494E-2 1.25851E-2
40 0.53772 5.34583E-3 -1.55917E-2
41 0.54697 2.10796E-3 -4.35601E-3
42 0.54843 -1.75512E-3 -5.15351E-4
43 0.89909 8.7169E-5 2.70945E-4
44 0.92942 1.57286E-3 -1.64296E-3
45 0.93417 6.95123E-4 1.60701E-3
46 0.96244 -3.93588E-3 2.94189E-3
47 0.96696 3.74624E-4 5.44625E-5
48 0.99185 -4.52151E-4 3.80727E-4
49 0.99455 1.72846E-3 5.54381E-4
50 0.99727 4.6888E-2 4.57348E-2
51 1.00000 5.38294E-4 1.96888E-3
52 1.00275 1.10893E-2 1.61512E-2
53 1.00551 -4.0533E-4 9.09979E-4
54 1.02954 -6.37199E-5 1.80244E-3
55 1.03472 1.88211E-3 -1.92746E-3
56 1.04061 2.45396E-4 1.07552E-4
57 1.06951 -5.12965E-4 -1.08887E-3
58 1.07581 3.37185E-2 -7.43833E-3
59 1.11346 3.7105E-4 1.15642E-3
60 1.11951 -2.20656E-3 -5.30286E-3
61 1.16035 5.18341E-4 -7.01326E-4
62 1.16693 -5.92305E-5 -3.2299E-4
63 1.21136 1.45827E-4 -2.08305E-4
64 13.66079 1.4385E-3 -8.87958E-3
65 14.76529 1.11128E-3 2.25731E-3
66 27.55455 3.59967E-3 1.30195E-2
67 31.81193 -1.679E-2 2.31416E-3
68 182.62118 -4.18327E-2 4.67983E-2
69 365.25998 6.18534E-2 9.45166E-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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