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)
07 Dec 2024 01:59:00
Latency
333
Level
1.09

Harmonics

Points count
6125221
First date
29 Apr 2011 19:11
Last date
06 Dec 2024 23:59

Click on following link to see data:

Harmonics Constatns
Comp # Period (day) Cos factor (m) Sin factor (m)
0 0.00000 1.13459E+0 0E+0
1 0.12877 8.2214E-5 -9.68426E-6
2 0.12886 2.0197E-4 1.80243E-4
3 0.12938 1.47038E-4 -1.07016E-4
4 0.14707 -1.15805E-4 3.1178E-5
5 0.16841 3.21086E-4 3.22632E-4
6 0.16857 -1.58712E-4 -1.13016E-3
7 0.17036 7.16637E-4 1.13216E-4
8 0.17052 -2.82673E-3 -1.32466E-3
9 0.17251 -1.04586E-3 1.1409E-3
10 0.17470 4.30407E-4 -2.50111E-4
11 0.19989 3.10733E-4 3.78206E-4
12 0.20545 7.9984E-4 -1.1529E-4
13 0.24966 -5.59475E-4 1.54212E-5
14 0.25000 3.56151E-4 3.32115E-4
15 0.25395 -6.64932E-4 -3.99944E-4
16 0.25431 -9.65719E-6 1.11455E-3
17 0.25631 8.89025E-5 -6.89503E-5
18 0.25667 -2.23348E-4 3.59392E-5
19 0.25876 4.59686E-4 -4.78309E-4
20 0.26122 -2.60296E-4 8.40283E-4
21 0.33303 3.33925E-4 1.54853E-3
22 0.34071 1.06187E-3 -9.90802E-5
23 0.34135 6.23273E-4 -4.51989E-4
24 0.34502 -3.25861E-3 3.15857E-3
25 0.34943 1.11168E-5 3.20335E-4
26 0.48977 -1.04761E-4 9.63973E-4
27 0.49109 9.49571E-4 -1.26126E-4
28 0.49863 1.12157E-2 4.99018E-3
29 0.49932 -1.06779E-3 3.64747E-4
30 0.50000 -3.89128E-2 -4.06553E-2
31 0.50798 2.25819E-3 1.02555E-2
32 0.50924 2.18188E-3 -1.04544E-3
33 0.51606 -4.87763E-3 4.97127E-3
34 0.51679 2.59233E-3 4.56956E-3
35 0.51753 -4.04612E-1 3.07091E-1
36 0.51826 1.45667E-3 -6.6003E-3
37 0.52608 -2.08486E-2 1.5351E-2
38 0.52743 1.02265E-1 6.79097E-2
39 0.53632 1.56928E-2 1.26078E-2
40 0.53772 5.31846E-3 -1.55249E-2
41 0.54697 2.06486E-3 -4.36923E-3
42 0.54843 -1.74316E-3 -4.9823E-4
43 0.89909 8.52701E-5 2.71945E-4
44 0.92942 1.47047E-3 -1.49011E-3
45 0.93417 7.82809E-4 1.70361E-3
46 0.96244 -3.92108E-3 2.82816E-3
47 0.96696 2.90324E-4 -2.07247E-5
48 0.99185 -6.20451E-4 4.20031E-4
49 0.99455 1.95253E-3 4.02367E-4
50 0.99727 4.56966E-2 4.54345E-2
51 1.00000 5.31632E-4 2.0845E-3
52 1.00275 1.08962E-2 1.618E-2
53 1.00551 -5.81015E-4 9.74653E-4
54 1.02954 -1.14205E-4 2.00973E-3
55 1.03472 1.7193E-3 -2.03086E-3
56 1.04061 3.15556E-4 1.54115E-6
57 1.06951 -6.80725E-4 -1.36267E-3
58 1.07581 3.25435E-2 -7.71644E-3
59 1.11346 3.11973E-4 1.34269E-3
60 1.11951 -2.28358E-3 -5.14364E-3
61 1.16035 5.50681E-4 -7.57089E-4
62 1.16693 7.50017E-5 -5.08125E-4
63 1.21136 1.2051E-4 -2.05167E-4
64 13.66079 2.12291E-3 -8.76604E-3
65 14.76529 1.45818E-3 2.19317E-3
66 27.55455 3.89972E-3 1.41033E-2
67 31.81193 -1.84422E-2 2.59288E-3
68 182.62118 -4.59175E-2 5.24602E-2
69 365.25998 6.44556E-2 1.03565E-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