gge 5013 lab ii – tidal analysis november 15 th , 2006 ian.church@unb

GGE 5013Lab II – Tidal Analysis

November 15th, 2006ian.church@unb.ca

04/19/23 GGE5013 Lab2 2

Tidal Analysis Lab

• Perform Analysis on 7 Tide Stations• Extract the Harmonic Constituents (T_Tide)• Compare Predicted Tides to the Original Tide• Extract the Tidal Residuals• Explain the Residuals using Meteorological

Data• Compare the Residuals at each Station

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T_Tide

• T_Tide Harmonic Analysis Toolbox for Matlab

• Developed by Rich Pawlowicz at UBC from IOS Tidal Package by Mike Foreman

Fortran Matlab

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Literature

• T_Tide Harmonic Analysis Toolbox for Matlab:

– R. Pawlowicz, B. Beardsley, and S. Lentz, "Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE", Computers and Geosciences 28 (2002), 929-937.

• IOS Tidal Package Manual:– Foreman, M.G.G., 1977. Manual for Tidal Heights Analysis and Prediction.

Pacific Marine Science Report 77-10, Institute of Ocean Sciences, Patricia Bay, Sidney, B.C., 58 pp. (2004 revision).

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T_Tide Programs

• t_tide.m

• t_predic.m*

• t_demo.m

• t_readme.m

Programs of Interest

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T_Tide Inputs

• Optional:– 'interval'– 'start time'– 'latitude'– 'inference‘– ‘shallow’– ‘…’

• Descriptions can be found in t_tide.m file

help t_tide

• Required:Array of Water Level Elevations [:,1]

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T_Tide Outputs

• Structure:– Constituent Names– Frequency– Amplitude, Amp Error, Phase, Phase Error

• New Predicted Time Series

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Example – Hydrocamp 2006

• St. Andrews, NB

St. Andrews, NB -- June 13th to 19th 2006

0

1

2

3

4

5

6

7

8

164

164

165

165

165

165

166

166

166

167

167

167

168

168

168

168

169

169

169

170

170

170

170

Wa

ter

Le

ve

l (m

)

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Matlab Example

• Load Data into Matlab

• Run t_tide– [Tide_Struct, Pred_Out] = t_tide(TideData,'interval',1/6, 'start time',

StartTime,'latitude',44+38/60);

– Above example for an array of 10 minute tide data

– StartTime is the beginning time of the tidal time series in Matlab serial date format created using “datenum” in Matlab (type “help datenum” in Matlab for usage)

– Latitude is the station latitude

• Save Predicted Tide & Examine Residuals

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Questions?

Station NameSt. John, NB Miguel

Eastport, ME Andy

Cutler, ME Blaine

Yarmouth, NS Shawn

North Head, NB Blair and Scott

Digby, NS Aluizio

Brier Island, NS Pim