netcdf frf/oceanography/waves/sig940-400/sig940-400.ncml {
  dimensions:
    station_name_length = 10;
    waveFrequency = 62;
    waveDirectionBins = 72;
    time = 4218;
  variables:
    char station_name(station_name_length=10);
      :long_name = "station name";
      :cf_role = "timeseries_id";
      :units = ;
      :short_name = "station_name";
      :_ChunkSizes = 10U; // uint

    double latitude;
      :_FillValue = -999.0; // double
      :units = "degrees_north";
      :standard_name = "latitude";
      :short_name = "lat";
      :long_name = "Latitude";

    double longitude;
      :_FillValue = -999.0; // double
      :units = "degrees_east";
      :standard_name = "longitude";
      :short_name = "lon";
      :long_name = "Longitude";

    double nominalDepth;
      :_FillValue = -999.0; // double
      :units = "m";
      :short_name = "Bottom Elevation";
      :long_name = "Bottom Elevation (NAVD88)";
      :description = "Nominal bottom vertical location from NAVD88";

    double gaugeElevation;
      :_FillValue = -999.0; // double
      :units = "m";
      :short_name = "Gauge Elevation";
      :long_name = "Gauge Elevation";
      :description = "Gauge Vertical Position from NAVD88";

    double waveFrequency(waveFrequency=62);
      :_FillValue = -999.0; // double
      :units = "s-1";
      :standard_name = "wave_frequency";
      :short_name = "Frequency";
      :long_name = "Spectral Band Center Frequency";
      :_ChunkSizes = 62U; // uint

    double waveDirectionBins(waveDirectionBins=72);
      :_FillValue = -999.0; // double
      :units = "degree";
      :short_name = "Direction";
      :long_name = "Band Center in Degrees";
      :_ChunkSizes = 72U; // uint

    double time(time=4218);
      :_FillValue = -999.0; // double
      :units = "seconds since 1970-01-01 00:00:00";
      :standard_name = "time";
      :long_name = "UTC Sample Time";
      :calendar = "gregorian";
      :short_name = "time";
      :_ChunkSizes = 1000U; // uint

    double gaugeDepth(time=4218);
      :_FillValue = -999.0; // double
      :units = "m";
      :short_name = "Gauge Depth";
      :long_name = "Sensor Depth Using Pressure.";
      :_ChunkSizes = 657U; // uint

    double bottomEelevation(time=4218);
      :_FillValue = -999.0; // double
      :units = "m";
      :short_name = "Bottom Elevation";
      :long_name = "Bottom Elevation (NAVD88)";
      :description = "Bottom vertical location from NAVD88 from altimeter, survey data, or nominal data.  See bottomElevationSource.";
      :_ChunkSizes = 657U; // uint

    byte bottomElevationSource(time=4218);
      :_FillValue = -99B; // byte
      :units = ;
      :short_name = "BottomZ source";
      :long_name = "Bottom elevation source flag (0=nominal depth, 1=altimeter, 2=bathymetric survey)";
      :coordinates = "lat lon";
      :_ChunkSizes = 657U; // uint

    double waveEnergyDensity(time=4218, waveFrequency=62);
      :_FillValue = -999.0; // double
      :units = "m2 s";
      :standard_name = "sea_surface_wave_variance_spectral_density";
      :short_name = "1D Wave Energy";
      :long_name = "Energy Density";
      :description = "Surface spectra, linear theory corrected, barometer adjusted, corrected if buried";
      :_ChunkSizes = 657U, 62U; // uint

    double directionalPeakSpread(time=4218);
      :_FillValue = -999.0; // double
      :units = "deg";
      :short_name = "spreadP";
      :long_name = "Directional Spectra Spread at Peak Frequency";
      :coordinates = "lat lon";
      :description = "Directional spread at peak frequency with cos(2*theta) circular moments";
      :_ChunkSizes = 657U; // uint

    double spectralWidthParameter(time=4218);
      :_FillValue = -999.0; // double
      :units = ;
      :short_name = "spreadP";
      :long_name = "Spectral Width Parameter";
      :valid_min = "0";
      :valid_max = "1";
      :coordinates = "lat lon";
      :description = "Spectral width of 1D spectra, (m0*m4 - m2^2)/(m0*m4)  (Cartwright & Longuet-Higgins, 1956)";
      :_ChunkSizes = 657U; // uint

    double directionalWaveEnergyDensity(time=4218, waveFrequency=62, waveDirectionBins=72);
      :_FillValue = NaN; // double
      :units = "m2 s deg-1";
      :standard_name = "sea_surface_wave_directional_variance_spectral_density";
      :short_name = "Energy Density";
      :long_name = "2D Wave Energy Density Spectrum";
      :_ChunkSizes = 1U, 62U, 72U; // uint

    double waveHs(time=4218);
      :_FillValue = -999.0; // double
      :units = "m";
      :standard_name = "sea_surface_wave_significant_height";
      :short_name = "Hs";
      :long_name = "Significant Wave Height";
      :coordinates = "lat lon";
      :description = "Significant wave height computed for spectral frequencies between 0.04 and 0.5 Hz";
      :_ChunkSizes = 657U; // uint

    double waveTp(time=4218);
      :_FillValue = -999.0; // double
      :units = "s";
      :standard_name = "sea_surface_wave_period_at_variance_spectral_density_maximum";
      :short_name = "Tp";
      :long_name = "Peak Spectral Period Between 2 and 25 Seconds";
      :coordinates = "lat lon";
      :description = "Period of a parobolic fit to the peak of the energy density spectrum using the peak and two surrounding points.  Computed for wave periods between 2 and 25 seconds";
      :_ChunkSizes = 657U; // uint

    double waveTm(time=4218);
      :_FillValue = -999.0; // double
      :units = "s";
      :standard_name = "sea_surface_wave_mean_period_from_variance_spectral_density_inverse_frequency_moment";
      :short_name = "Tm";
      :long_name = "Mean Spectral Period";
      :coordinates = "lat lon";
      :description = "Period for the mean of the energy density spectrum";
      :_ChunkSizes = 657U; // uint

    double waveTm1(time=4218);
      :_FillValue = -999.0; // double
      :units = "s";
      :standard_name = "sea_surface_wave_mean_period_from variance_spectral_density_first_frequency_moment";
      :short_name = "Tm1";
      :long_name = " 1st Moment Mean Spectral Period";
      :coordinates = "lat lon";
      :description = "Period for the 1st moment mean of the energy density spectrum";
      :_ChunkSizes = 657U; // uint

    double waveTm2(time=4218);
      :_FillValue = -999.0; // double
      :units = "s";
      :standard_name = "sea_surface_wave_mean_period_from variance_spectral_density_second_frequency_moment";
      :short_name = "Tm2";
      :long_name = " 2nd Moment Mean Spectral Period";
      :coordinates = "lat lon";
      :description = "Period for the 2nd moment mean of the energy density spectrum";
      :_ChunkSizes = 657U; // uint

    double wavePeakDirectionPeakFrequency(time=4218);
      :_FillValue = -999.0; // double
      :units = "degree";
      :standard_name = "sea_surface_wave_from_direction";
      :short_name = "thetaP";
      :long_name = "Wave Direction at the Peak of the Frequency-Direction Spectrum";
      :coordinates = "lat lon";
      :description = "Wave direction is from true north (MET convention)";
      :_ChunkSizes = 657U; // uint

    double waveMeanDirection(time=4218);
      :long_name = "Mean Wave Direction of 2D Spectrum";
      :description = "Wave direction is from true north (MET convention), energy weighted over and computed from a1 & b1";
      :_FillValue = -999.0; // double
      :units = "degree";
      :short_name = "thetaM";
      :coordinates = "lat lon";
      :_ChunkSizes = 657U; // uint

    double waveMeanDirectionPeakFrequency(time=4218);
      :_FillValue = -999.0; // double
      :units = "degree";
      :short_name = "thetaMp";
      :long_name = "Wave Mean Direction at the Peak Frequency";
      :coordinates = "lat lon";
      :description = "Wave direction is from true north (MET convention), energy weighted at peak frequency";
      :_ChunkSizes = 657U; // uint

    double wavePrincipleDirection(time=4218);
      :_FillValue = -999.0; // double
      :units = "degree";
      :short_name = "thetaM2";
      :long_name = "Wave Principle Direction of 2D Spectrum";
      :coordinates = "lat lon";
      :description = "Wave direction is from true north (MET convention), energy weighted over and computed from a2 & b2";
      :_ChunkSizes = 657U; // uint

    double waveA1Value(time=4218, waveFrequency=62);
      :_FillValue = -999.0; // double
      :units = ;
      :short_name = "a1";
      :long_name = "a1 Directional Fourier Coefficient";
      :coordinates = "lat lon";
      :description = "a1 Fourier coefficient";
      :_ChunkSizes = 657U, 62U; // uint

    double waveB1Value(time=4218, waveFrequency=62);
      :_FillValue = -999.0; // double
      :units = ;
      :short_name = "b1";
      :long_name = "b1 Directional Fourier Coefficient";
      :coordinates = "lat lon";
      :description = "b1 Fourier coefficient";
      :_ChunkSizes = 657U, 62U; // uint

    double waveA2Value(time=4218, waveFrequency=62);
      :_FillValue = -999.0; // double
      :units = ;
      :short_name = "a2";
      :long_name = "a2 Directional Fourier Coefficient";
      :coordinates = "lat lon";
      :description = "a2 Fourier coefficient";
      :_ChunkSizes = 657U, 62U; // uint

    double waveB2Value(time=4218, waveFrequency=62);
      :_FillValue = -999.0; // double
      :units = ;
      :short_name = "b2";
      :long_name = "b2 Directional Fourier Coefficient";
      :coordinates = "lat lon";
      :description = "b2 Fourier coefficient";
      :_ChunkSizes = 657U, 62U; // uint

    byte qcFlagE(time=4218);
      :_FillValue = -99B; // byte
      :units = ;
      :short_name = "QC_flag_E";
      :long_name = "Quality Control Flag Value for Energy Estimates";
      :coordinates = "lat lon";
      :description = "Realtime QC flags for spectral estimates";
      :flag_meanings = "1=passed, 2=not set, 3=questionable, 4=failed";
      :_ChunkSizes = 657U; // uint

    byte qcFlagD(time=4218);
      :_FillValue = -99B; // byte
      :units = ;
      :short_name = "QC_flag_D";
      :long_name = "Quality Control Flag Value for Directional Spectra Estimates";
      :coordinates = "lat lon";
      :description = "Realtime QC flags for spectral direction estimates";
      :flag_meanings = "1=passed, 2=not set, 3=questionable, 4=failed";
      :_ChunkSizes = 657U; // uint

    byte PorAST(time=4218);
      :_FillValue = -99B; // byte
      :units = ;
      :short_name = "Pressure or AST";
      :long_name = "Pressure or Acoustic Surface Track";
      :coordinates = "lat lon";
      :description = "Flag indicating whether pressure (1) or acoustic surface track (2) time series was used to derive waveEnergyDensity and related parameters";
      :_ChunkSizes = 657U; // uint

  // global attributes:
  :featureType = "timeSeries";
  :title = "sig940-400";
  :station_name = "sig940-400";
  :summary = "USACE/COAB data collected by a bottom mounted (looking up) Nortek Signature 1000, approximately 400m offshore of Duck (FRF), NC at a nominal depth of -4.5m NAVD88.  Directional spectra are computed using standard SUV/PUV analysis. SUV is favored but switches to PUV if AST is noisy. Switching to PUV is most common in energetic conditions with breaking waves. Data collection is hard-wired and analyzed hourly with 34 minute timeseries records.  Two dimensional frequency-direction spectra are computed using an Iterative Maximum Likelihood Estimator (MLE) method.";
  :history = "2024-10-24:data set created";
  :source = "In situ observations from FRF-ocean_waves_sig940-400_YYYYMM.mat";
  :sourceUrl = "(local files)";
  :standard_name_vocabulary = "CFv25";
  :Metadata_Conventions = "Unidata Dataset Discovery v1.0, CF-1.6";
  :metadata_link = "N/A";
  :Conventions = "CF-1.6";
  :creator_name = "USACE/CHL/COAB";
  :creator_url = "http://frf.usace.army.mil";
  :creator_email = "frfwebmaster@usace.army.mil";
  :license = "These data may be redistributed and used without restriction. Data are intended for scholarly use by the research community, with the express agreement that users will properly acknowledge the USACE Field Research Facility and the supporting investigator(s). Use or reproduction of these data for commercial purposes is prohibited without prior written permission.";
  :keywords_vocabulary = "Global Change Master Directory (GCMD) Earth Science Keywords; CF Standard Name Table (v23, 23 March 2013)";
  :keywords = "Oceans > Ocean Waves > Wave Frequency, Oceans > Ocean Waves > Wave Height, Oceans > Ocean Waves > Wave Period, Oceans > Ocean Waves > Wave Spectra, Oceans > Ocean Waves > Wave Direction, DOD > DOD/USARMY/USACE/CHL/FRF > Field Research Facility, Coastal And Hydraulics Laboratory,U. S. Army Corps Of Engineers, U.S. Army, U. S. Department Of Defense, sea_surface_wave_variance_spectral_density, sea_surface_wave_significant_height, sea_surface_wave_from_direction,  sea_surface_wave_directional_variance_spectral_density;";
  :processing = "realtime";
  :organization = "USACE/CHL/COAB";
  :publisher_url = "http://frf.usace.army.mil";
  :infoUrl = "http://frf.usace.army.mil";
  :publisher_email = "frfwebmaster@usace.army.mil";
  :publisher_name = "USACE/CHL/COAB";
  :format_version = "v1.0";
  :institution = "USACE/CHL/COAB";
  :contact = "USACE/CHL/COAB";
  :contact_info = "USACE/CHL/COAB";
  :contact_role = "Owner";
  :contributor_name = "USACE/CHL/COAB";
  :contributor_role = "USACE/CHL/COAB";
  :naming_authority = "FRF";
  :origin = "USACE/CHL/COAB";
  :date_created = "2025-03-31";
  :date_issued = "2025-03-31";
  :acknowledgement = "Data are provided by the Field Research Facility; Coastal Observations & Analysis Branch; US Army Corps of Engineers, Duck, North Carolina.";
  :project = "USACE/COAB observations";
  :id = "FRF-ocean_waves_sig940-400";
  :processing_level = "L1";
  :geospatial_vertical_units = "m";
  :geospatial_vertical_resolution = 0.1; // double
  :geospatial_vertical_min = -6.0; // double
  :geospatial_vertical_max = 3.0; // double
  :geospatial_vertical_origin = "sea surface";
  :geospatial_lat_min = 36.186779; // double
  :geospatial_lat_max = 36.186779; // double
  :geospatial_lat_units = "degrees_north";
  :geospatial_lon_min = -75.748681; // double
  :geospatial_lon_max = -75.748681; // double
  :geospatial_lon_units = "degrees_east";
  :geospatial_vertical_positive = "up";
  :time_coverage_start = "2025-03-01T00:00:07";
  :time_coverage_end = "2025-03-31T23:00:10";
  :deployment_start = "2024-10-23T22:00:00Z";
  :platform = "Nortek Signature1000";
  :instrument = "Nortek Signature1000";
  :cross_shore_angle_units = "degrees";
  :cross_shore_angle_description = "cross shore angle at the USACE FRF site in DUCK, NC, clockwise from true north";
  :cross_shore_angle = 71.8; // double
}