1. Lab 2 – Tidal Analysis GGE5013 Ian Church

2. Tidal Analysis Lab Perform Harmonic Analysis on 7 Tide Stations Extract the Harmonic Constituents ( using 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 –Done in class with residuals from each station

3. Run t_tide Save Data from Lab2 webpage –Only Need One Column of Tide Data (TideData) –Need to know Sampling Interval (Interval in hours) 2.247 2.456 2.678 2.885 … [Tide_Struct, Pred_Out] = t_tide(TideData,'interval',1/6, 'start time', StartTime,'latitude',44+38/60);

4. Run t_tide (2) New Issue: Time –Need to Reference the Constituent Phase –Add the Start Time of the Tidal Data Series StartTime  Matlab Serial Date Number StartTime = datenum(2006,6,22,0,0,0) [Tide_Struct, Pred_Out] = t_tide(TideData,'interval',1/6, 'start time', StartTime,'latitude',44+38/60);

5. Run t_tide (3) While we are at it, why not perform nodal corrections. Should give us a slightly better solution Add the Latitude in Decimal Degrees [Tide_Struct, Pred_Out] = t_tide(TideData,'interval',1/6, 'start time', StartTime,'latitude',44+38/60);

6. Nodal Corrections See Reference Material… Aids in Resolving Satellite Constituents

7. Compare the Amplitudes and Phases from t_tide to the Published Harmonics (from Bluefile or NOAA) –Correct Time Zone –NOAA  Can Change Time Zone for Harmonic Constituents –Bluefile  Local Time Add Time offset to StartTime variable StartTime = datenum(Year,Month,Day,Hour+Offset,Minute,Second) Notes

8. Questions Lab 2? Lab 1?