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U.S. Geological Survey Open-File Report 2012-1219

Carolinas Coastal Change Processes Project data report for nearshore observations at Cape Hatteras, North Carolina, February 2010

Tidal Analysis

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Amplitude and phase of principal tidal constituents were computed using the tidal analysis program T_TIDE (Pawlowicz and others 2002). The principal constituents are K1, O1, M2, N2, and S2. This report includes the full output from T_TIDE for each data record. Table entries marked with a "C" denote the computation of tidal constituents from the entire deployment. The duration of time series used to compute the harmonics is different for each instrument, depending on instrument deployment and recovery times (see Field Mooring Log), and data availability.

Table headings for T_TIDE output:

  • tide: tidal constituent freq: frequency (cycles/hour)
  • major: major axis of tidal ellipse (for current observations) in centimeters per second (cm/s)
  • emaj: error estimate for major axis (cm/s)
  • minor: minor axis of tidal ellipse (cm/s)
  • emin: error estimate for minor axis (cm/s)
  • inc: inclination of major axis (counter clockwise from east) (degrees)
  • einc: error estimate for inclination (degrees)
  • phase: phase of major axis (degrees)
  • ephase: error estimate of phase (degrees)
  • snr: signal-to-noise ratio
Nearshore sites Pressure at
1 mab
Current velocity
Surface Bottom
N1 Output Output Output
N2 Output Output Output
N3 Output Output Output
N4 Output Output Output
N5 Output Output Output
N6 Output Output Output
N8 Output Output Output
N9 Output Output Output
N11 Output Output Output
N12 Output Output Output
Offshore sites Pressure at
1 mab
Current velocity
Surface Bottom
O1 Output Output Output
O2 Output Output Output
O3 Output Output Output

Significant constituents (those with signal-to-noise ratio in the last column greater than 1) are indicated with an asterisk.

mab= meters above bottom

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