HDF5 file, superblock version 2
group /
	attribute Conventions = "CF-1.6, ACDD-1.3"
	attribute acknowledgement = "This project is funded by NOAA STAR and NCEI to CICS-MD."
	attribute cdm_data_type = "Trajectory"
	attribute comment = "Additional information from original files:original title = HENRY B. BIGELOW Meteorological Data;site = HENRY B. BIGELOW;data provider contact info = Center for Ocean-Atmospheric Prediction Studies, The Florida State University, Tallahassee, FL, 32306-2840, USA"
	attribute contributor_name = "NCEI; Ocean Science Branch; SAMOS; Senior Survey Tech Geoff Shook; NOAA"
	attribute contributor_role = "National Archive; Group Discussion; Data Assemble; Data Provider; Facility"
	attribute creator_email = "zhankun.wang@noaa.gov"
	attribute creator_institution = "NOAA National Centers for Environmental Information (NCEI)"
	attribute creator_name = "Zhankun Wang"
	attribute creator_type = "person"
	attribute creator_url = "https://www.nodc.noaa.gov/cgi-bin/OAS/prd/person/details/4843"
	attribute date_created = "2017-06-23T03:02:35Z"
	attribute date_issued = "2017-07-01T00:00:00Z"
	attribute date_metadata_modified = "2017-06-23T03:02:35Z"
	attribute date_modified = "2017-06-23T03:02:35Z"
	attribute featureType = "trajectory"
	attribute geospatial_bounds = "POLYGON ((-70.0000 41.1200,-70.0000 44.2300,-65.8900 44.2300,-65.8900 41.1200,-70.0000 41.1200))"
	attribute geospatial_bounds_crs = "EPSG:4326"
	attribute geospatial_lat_max = 44.23
	attribute geospatial_lat_min = 41.12
	attribute geospatial_lat_units = "degrees_north"
	attribute geospatial_lon_max = -65.89
	attribute geospatial_lon_min = -70.0
	attribute geospatial_lon_units = "degrees_east"
	attribute history = "2017-06-23T03:02:35Z: Created by Z.Wang/NCEI."
	attribute id = "WTDF_201706_7406V1"
	attribute institution = "National Centers for Environmental Information (NCEI), NOAA"
	attribute instrument = "SeaBird 38 S/#1225; unknown; SBE45"
	attribute instrument_vocabulary = "ACDD Keyword Version 8.1"
	attribute keywords = "EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > SEA SURFACE TEMPERATURE,EARTH SCIENCE > OCEANS > SALINITY/DENSITY > SALINITY,EARTH SCIENCE > OCEANS > SALINITY/DENSITY > CONDUCTIVITY"
	attribute keywords_vocabulary = "Global Change Master Directory (GCMD). 2015. GCMD Keywords, Version 8.1."
	attribute license = "These data may be redistributed and used without restriction."
	attribute metadata_link = (empty)
	attribute naming_authority = "gov.noaa.ncei"
	attribute ncei_template_version = "NCEI_NetCDF_Trajectory_Template_v2.0"
	attribute platform = "HENRY B. BIGELOW"
	attribute processing_level = "Quality-controlled and restructured to one file per vessel per month per wmo square."
	attribute product_version = "GTSG V1.0"
	attribute project = "NCEI Global Thermosalinograph Data Stewardship Project"
	attribute publisher_email = "ncei.info@noaa.gov"
	attribute publisher_institution = "NOAA National Centers for Environmental Information (NCEI)"
	attribute publisher_name = "NCEI Data Manager"
	attribute publisher_type = "institution"
	attribute publisher_url = "https://www.ncei.noaa.gov/"
	attribute references = (empty)
	attribute sea_name = "World-Wide Distribution"
	attribute source = "SAMOS: WTDF_20170613v10001.nc; WTDF_20170613v10002.nc; WTDF_20170614v10001.nc; WTDF_20170614v10002.nc; WTDF_20170615v10001.nc; WTDF_20170615v10002.nc; WTDF_20170616v10001.nc; WTDF_20170617v10001.nc; WTDF_20170617v10002.nc; WTDF_20170617v10003.nc; WTDF_20170617v10004.nc; WTDF_20170618v10001.nc; WTDF_20170619v10001.nc; WTDF_20170620v10001.nc; WTDF_20170621v10001.nc; WTDF_20170621v10002.nc"
	attribute standard_name_vocabulary = "CF Standard Name Table v31"
	attribute summary = "The overarching goal of the Global Thermosalinograph (TSG) Project is to serve the broader community by providing a well-organized, uniformly quality-controlled thermosalinograph database. This data file is a re-representation of the thermosalinograph data archived at the NOAA National Centers for Environmental Information (NCEI)."
	attribute time_coverage_duration = "P1W1DT1M"
	attribute time_coverage_end = "2017-06-21T14:57:00Z"
	attribute time_coverage_resolution = "PT1M"
	attribute time_coverage_start = "2017-06-13T14:56:00Z"
	attribute title = "Thermosalinograph data collected aboard HENRY B. BIGELOW in WMO square 7406 from 2017-06-13T14:56:00Z to 2017-06-21T14:57:00Z."
	attribute uuid = "e348a599-4994-43b0-8f5b-429e24e3b2a8"
dataset /L1: float32, shape (6)
dataset /L2: float32, shape (5)
dataset /common_variables_qc: int16, shape (10650, 1)
	attribute _FillValue = -99
	attribute comment = "Derived from the secondary level flags. For a value to be flagged as 1, it must pass all the associated tests in the secondary QC."
	attribute default_value = 0
	attribute flag_meanings = "no_QC_was_performed accepted_value  probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed interpolated_value missing_value"
	attribute flag_values = 0, 1, 2, 3, 4, 5, 8, 9
	attribute long_name = "overall quality flag of common variables (platform, time, location, platform_speed, land and flow_rate)"
	attribute references = (empty)
dataset /common_variables_qc_L: int16, shape (10650, 6)
	attribute _FillValue = -99
	attribute comment = "The primary level flags are derived from these flags."
	attribute default_value = 0
	attribute flag_comment_row1 = "This test requires the data arrives from a platform with a valid callsign. If this test fails, the record is flagged as 4, otherwsie it is flagged as 1."
	attribute flag_comment_row2 = "This test requires reasonable values for the time of the observations. Time needs to be greater than 1970/01/01 or less than the last modification time of this file (flagged as 1). If this test fails, the record is flagged as 4. For duplicate time, both duplicate time records are flagged as 3."
	attribute flag_comment_row3 = "This test requires latitude values -90<latitude<90 and longitude values -180<=longitude<=180."
	attribute flag_comment_row5 = "This test checks the elevation of the observation location. The ETOPO1 file is used to see if each record is located at sea. In the coastal regions, the elevation from ETOPO1 might lead to wrong flags (actual depth <0m, but elevation found from ETOPO1 >0m), so we set up three flag values (2-4) to indicate the possibilities of landlocked data records. le:less than or equal to, gt:greater than."
	attribute flag_comment_row6 = "This test is only performed when the water volume flow rate through the thermosalinograph is available in the data. When flow_rate<3Min/L, the pipeline might be blocked and bubbles can be generated. 50L/Min is the maximum flow value for most TSG. le:less than or equal to, gt:greater than, lt:less than."
	attribute flag_comments_row4 = "This test check that the platform speed between consecutive points is within a valid range. The first record on file always flagged as 1."
	attribute flag_meanings_row1 = "platform_information_found platform_inforamtion_not_found"
	attribute flag_meanings_row2 = "valid_time duplicate_time invalid_time"
	attribute flag_meanings_row3 = "valid_latitude_and_longitude invalid_latitude_or_longitude missing_location_observations"
	attribute flag_meanings_row4 = "platform_speed_less_than_20_meter_per_second platform_speed_greater_than_20_meter_per_second"
	attribute flag_meanings_row5 = "no_landlocked_check_was_performed elevation_le_0m elevation_gt_0m_but_le_3m elevation_gt_3m_but_le_10m elevation_gt_10m"
	attribute flag_meanings_row6 = "no_flow_rate_check_was_performed flow_rate_gt_3L_per_Min_but_le_50L_per_Min flow_rate_lt_3L_per_Min_or_gt_50L_per_Min"
	attribute flag_values_row1 = 1, 4
	attribute flag_values_row2 = 1, 3, 4
	attribute flag_values_row3 = 1, 4, 9
	attribute flag_values_row4 = 1, 4
	attribute flag_values_row5 = 0, 1, 2, 3, 4
	attribute flag_values_row6 = 0, 1, 4
	attribute long_name = "quality flag of common variables secondary level"
	attribute references = (empty)
	attribute row_meanings = "row1=platform_check row2=time_check row3=location_check row4=shipspeed_check row5=landlocked_check row6=flowrate_check"
dataset /conductivity: float32, shape (10650, 1)
	attribute _FillValue = -9999.0
	attribute ancillary_variables = "conductivity_qc conductivity_qc_L"
	attribute average_center = "unknown"
	attribute average_length = 60
	attribute average_method = "average"
	attribute cell_methods = "time: point"
	attribute comment = "Name in original file: CNDC"
	attribute coordinates = "time lat lon"
	attribute coverage_content_type = "physicalMeasurement"
	attribute data_precision = -9999.0
	attribute grid_mapping = "crs"
	attribute instrument = "instrument1"
	attribute long_name = "Sea water electrical conductivity"
	attribute platform = "platform1"
	attribute sampling_rate = 1.0
	attribute standard_name = "sea_water_electrical_conductivity"
	attribute units = "S/meter"
	attribute valid_max = 7
	attribute valid_min = 0
dataset /conductivity_qc: int16, shape (10650, 1)
	attribute _FillValue = -99
	attribute comment = "Derived from the secondary level flags. For a value to be flagged as 1, it must pass all the associated tests in the secondary QC and all the common tests."
	attribute default_value = 0
	attribute flag_meanings = "no_QC_was_performed accepted_value  probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed interpolated_value missing_value"
	attribute flag_values = 0, 1, 2, 3, 4, 5, 8, 9
	attribute long_name = "quality flag of conductivity"
	attribute references = (empty)
dataset /conductivity_qc_L: int16, shape (10650, 5)
	attribute _FillValue = -99
	attribute comment = "The primary level flags are derived from these flags."
	attribute default_value = 0
	attribute flag_comment_row1 = "Only global range check was performed on conductivity."
	attribute flag_comment_row2 = "Each measurement is compared against a seasonal climatology (WOD, 5 degree by 5 degree, seasonal, provided by Tim Boyer, NCEI). If there is no climatology information for the location of this record, it is flagged as 0. Other flag values are 1: |X-Xmean| <= 2*sigma; 2: 2*sigma < |X-Xmean| <= 3*sigma; 3:3*sigma < |X-Xmean| <= 4*sigma; 4:|X-Xmean| > 4*sigma. Where X is the value tested, Xmean is the corresponding value of the climatology, and sigma is the standard deviation of the climatolgy."
	attribute flag_comment_row3 = "This test is failed when there is no difference in the values of the measured parameters during a six-hour or longer period."
	attribute flag_comment_row4 = "This test requires that the difference between sequential conductivity measurements remains below a certain limit. For every record, a test value Xtest = |X2-(X3+X1)/2| -|(X3-X1)/2|, where X2 is the conductivity being tested, and X1 and X3 are the previous and next measurements, respectively, is determined. The test value X2 is flagged as 4 when Xtest > 0.18 S/m, otherwise it is flagged as 1."
	attribute flag_comment_row5 = "This test requires a limit for the difference between adjacent conductivity measurements. For every record a test value Xtest = |X2-(X3+X1)/2|, where X2 is the conductivity being tested and X1 and X3 are the previous and next values, respectively, is determined. The X2 value is flagged as 4 when Xtest > 0.3 S/m, otherwise it is flagged as 1."
	attribute flag_meanings_row1 = "no_global_range_check_was_performed within_the_global_range conductivity_greater_than_7_or_less_than_0 missing_value"
	attribute flag_meanings_row2 = "no_climatology_analysis_was_performed less_than_2sigma  greater_than_2sigma_but_less_than_3sigma greater_than_3sigma_but_less_than_4sigma greater_than_4sigma"
	attribute flag_meanings_row3 = "passed_the_constant_value_test failed_the_constant_value_test"
	attribute flag_meanings_row4 = "passed_spike_test falied_spike_test"
	attribute flag_meanings_row5 = "passed_gradient_test falied_gradient_test"
	attribute flag_values_row1 = 0, 1, 4, 9
	attribute flag_values_row2 = 0, 1, 2, 3, 4
	attribute flag_values_row3 = 1, 3
	attribute flag_values_row4 = 1, 4
	attribute flag_values_row5 = 1, 4
	attribute long_name = "quality flag of conductivity secondary level"
	attribute references = (empty)
	attribute row_meanings = "row1=regional/global_range_check row2=climatology_control row3=constant_value_check row4=spike_check row5=gradient_check"
dataset /crs: int32, shape ()
	attribute comment = (empty)
	attribute epsg_code = "EPSG:4326"
	attribute grid_mapping_name = "latitude_longitude"
	attribute inverse_flattening = 298.257223563
	attribute semi_major_axis = 6378137.0
dataset /instrument1: string(1), shape (1, 50)
	attribute centerline_offset = -9999.0
	attribute comment = "instrument information"
	attribute depth_of_water_intake = -6.0
	attribute distance_from_bow = -9999.0
	attribute long_name = "SBE45"
	attribute originator_units = "siemens meter-1"
dataset /instrument2: string(1), shape (1, 50)
	attribute centerline_offset = (empty)
	attribute comment = "instrument information"
	attribute depth_of_water_intake = (empty)
	attribute distance_from_bow = (empty)
	attribute long_name = "unknown"
	attribute originator_units = "degrees (+E)"
dataset /lat: float32, shape (10650, 1)
	attribute _FillValue = -9999.0
	attribute ancillary_variables = "common_variables_qc common_variables_qc_L"
	attribute average_center = "time at end of period"
	attribute average_length = 60
	attribute average_method = "average"
	attribute axis = "Y"
	attribute comment = (empty)
	attribute data_precision = -9999.0
	attribute instrument = "instrument2"
	attribute long_name = "latitude"
	attribute sampling_rate = 1.0
	attribute standard_name = "latitude"
	attribute units = "degrees_north"
	attribute valid_max = 90.0
	attribute valid_min = -90.0
dataset /lon: float32, shape (10650, 1)
	attribute _FillValue = -9999.0
	attribute ancillary_variables = "common_variables_qc common_variables_qc_L"
	attribute average_center = "time at end of period"
	attribute average_length = 60
	attribute average_method = "average"
	attribute axis = "X"
	attribute comment = (empty)
	attribute data_precision = -9999.0
	attribute instrument = "instrument2"
	attribute long_name = "longitude"
	attribute sampling_rate = 1.0
	attribute source = (empty)
	attribute standard_name = "longitude"
	attribute units = "degrees_east"
	attribute valid_max = 180.0
	attribute valid_min = -180.0
dataset /obs: float32, shape (10650)
dataset /platform1: string(1), shape (1, 50)
	attribute ATDB_code = "10926"
	attribute ICES_code = "33HH"
	attribute IMO_code = "9349057"
	attribute call_sign = "WTDF"
	attribute comment = "Original_ship_name = unknown at this time;C.s.WQ4000;built 1963;decom-d as NOAA Ship 10.2002"
	attribute long_name = "HENRY B. BIGELOW"
	attribute wod_code = "9305"
dataset /sea_surface_salinity: float32, shape (10650, 1)
	attribute _FillValue = -9999.0
	attribute ancillary_variables = "salinity_qc salinity_qc_L"
	attribute average_center = "time at end of period"
	attribute average_length = 60
	attribute average_method = "average"
	attribute cell_methods = "time: point"
	attribute comment = "Name in original file: SSPS"
	attribute coordinates = "time lat lon"
	attribute coverage_content_type = "physicalMeasurement"
	attribute data_precision = -9999.0
	attribute grid_mapping = "crs"
	attribute instrument = "instrument1"
	attribute long_name = "Sea surface salinity"
	attribute platform = "platform1"
	attribute sampling_rate = 1.0
	attribute standard_name = "sea_surface_salinity"
	attribute units = "1e-3"
	attribute valid_max = 40.0
	attribute valid_min = 0.0
dataset /sea_surface_salinity_qc: int16, shape (10650, 1)
	attribute _FillValue = -99
	attribute comment = "Derived from the secondary level flags. For a value to be flagged as 1, it must pass all the associated tests in the secondary QC and all the common tests."
	attribute default_value = 0
	attribute flag_meanings = "no_QC_was_performed accepted_value  probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed interpolated_value missing_value"
	attribute flag_values = 0, 1, 2, 3, 4, 5, 8, 9
	attribute long_name = "quality flag of sea surface salinity"
	attribute references = (empty)
dataset /sea_surface_salinity_qc_L: int16, shape (10650, 5)
	attribute _FillValue = -99
	attribute comment = "The primary level flags are derived from these flags."
	attribute default_value = 0
	attribute flag_comment_row1 = "This test applies a gross filter on observed values to find whether they are in the permitted range. No global range check was performed as the global range is always >= regional range. The WOD (World Ocean Database) regional range values (at 10m) were used in this test. The minimum and maximum of the range vary with files and can be found in the attributes of each varaible."
	attribute flag_comment_row2 = "Each measurement is compared against a seasonal climatology (WOD, 5 degree by 5 degree, seasonal, provided by Tim Boyer, NCEI). If there is no climatology information for the location of this record, it is flagged as 0. Other flag values are 1: |X-Xmean| <= 2*sigma; 2: 2*sigma < |X-Xmean| <= 3*sigma; 3:3*sigma < |X-Xmean| <= 4*sigma; 4:|X-Xmean| > 4*sigma. Where X is the value tested, Xmean is the corresponding value of the climatology, and sigma is the standard deviation of the climatolgy."
	attribute flag_comment_row3 = "This test is failed when there is no difference in the values of the measured parameters during a six-hour or longer period."
	attribute flag_comment_row4 = "This test requires that the difference between sequential salinity measurements remains below a certain limit. For every record, a test value Xtest = |X2-(X3+X1)/2| -|(X3-X1)/2|, where X2 is the salinity being tested, and X1 and X3 are the previous and next measurements, respectively, is determined. The test value X2 is flagged as 4 when Xtest > 0.9, otherwise it is flagged as 1."
	attribute flag_comment_row5 = "This test requires a limit for the difference between adjacent salinity measurements. For every record a test value Xtest = |X2-(X3+X1)/2|, where X2 is the salinity being tested and X1 and X3 are the previous and next values, respectively, is determined. The X2 value is flagged as 4 when Xtest > 1.5, otherwise it is flagged as 1."
	attribute flag_meanings_row1 = "no_regional_range_check_was_performed within_the_regional_range outside_of_the_regional_range missing_value"
	attribute flag_meanings_row2 = "no_climatology_analysis_was_performed less_than_2sigma  greater_than_2sigma_but_less_than_3sigma greater_than_3sigma_but_less_than_4sigma greater_than_4sigma"
	attribute flag_meanings_row3 = "passed_the_constant_value_test failed_the_constant_value_test"
	attribute flag_meanings_row4 = "passed_spike_test falied_spike_test"
	attribute flag_meanings_row5 = "passed_gradient_test falied_gradient_test"
	attribute flag_values_row1 = 0, 1, 4, 9
	attribute flag_values_row2 = 0, 1, 2, 3, 4
	attribute flag_values_row3 = 1, 3
	attribute flag_values_row4 = 1, 4
	attribute flag_values_row5 = 1, 4
	attribute long_name = "quality flag of sea surface salinity secondary level"
	attribute references = (empty)
	attribute row_meanings = "row1=regional/global_range_check row2=climatology_control row3=constant_value_check row4=spike_check row5=gradient_check"
dataset /sea_surface_temperature: float32, shape (10650, 1)
	attribute _FillValue = -9999.0
	attribute ancillary_variables = "sea_surface_temperature_qc sea_surface_temperature_qc_L"
	attribute average_center = "time at end of period"
	attribute average_length = 60
	attribute average_method = "average"
	attribute cell_methods = "time: point"
	attribute comment = "Name in original file: TS"
	attribute coordinates = "time lat lon"
	attribute coverage_content_type = "physicalMeasurement"
	attribute data_precision = -9999.0
	attribute grid_mapping = "crs"
	attribute instrument = "instrument1"
	attribute long_name = "Sea surface temperature"
	attribute platform = "platform1"
	attribute sampling_rate = 1.0
	attribute standard_name = "sea_surface_temperature"
	attribute units = "degree_Celsius"
	attribute valid_max = 35.0
	attribute valid_min = -3.0
dataset /sea_surface_temperature_qc: int16, shape (10650, 1)
	attribute _FillValue = -99
	attribute comment = "Derived from the secondary level flags. For a value to be flagged as 1, it must pass all the associated tests in the secondary QC and all the common tests."
	attribute default_value = 0
	attribute flag_meanings = "no_QC_was_performed accepted_value  probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed interpolated_value missing_value"
	attribute flag_values = 0, 1, 2, 3, 4, 5, 8, 9
	attribute long_name = "quality flag of sea surface temperature"
	attribute references = (empty)
dataset /sea_surface_temperature_qc_L: int16, shape (10650, 5)
	attribute _FillValue = -99
	attribute comment = "The primary level flags are derived from these flags."
	attribute default_value = 0
	attribute flag_comment_row1 = "This test applies a gross filter on observed values to find whether they are in the permitted range. No global range check was performed as the global range is always >= regional range. The WOD (World Ocean Database) regional range values (at 10m) were used in this test. The minimum and maximum of the range vary with files and can be found in the attributes of each varaible."
	attribute flag_comment_row2 = "Each measurement is compared against a seasonal climatology (WOD, 5 degree by 5 degree, seasonal, provided by Tim Boyer, NCEI). If there is no climatology information for the location of this record, it is flagged as 0. Other flag values are 1: |X-Xmean| <= 2*sigma; 2: 2*sigma < |X-Xmean| <= 3*sigma; 3:3*sigma < |X-Xmean| <= 4*sigma; 4:|X-Xmean| > 4*sigma. Where X is the value tested, Xmean is the corresponding value of the climatology, and sigma is the standard deviation of the climatolgy."
	attribute flag_comment_row3 = "This test is failed when there is no difference in the values of the measured parameters during a six-hour or longer period."
	attribute flag_comment_row4 = "This test requires that the difference between sequential temperature measurements remains below a certain limit. For every record, a test value Xtest = |X2-(X3+X1)/2| -|(X3-X1)/2|, where X2 is the temperature being tested, and X1 and X3 are the previous and next measurements, respectively, is determined. The test value X2 is flagged as 4 when Xtest > 6.0 degree Celsius, otherwise it is flagged as 1."
	attribute flag_comment_row5 = "This test requires a limit for the difference between adjacent temperature measurements. For every record a test value Xtest = |X2-(X3+X1)/2|, where X2 is the temperature being tested and X1 and X3 are the previous and next values, respectively, is determined. The X2 value is flagged as 4 when Xtest > 9.0 degree Celsius, otherwise it is flagged as 1."
	attribute flag_meanings_row1 = "no_regional_range_check_was_performed within_the_regional_range outside_of_the_regional_range missing_value"
	attribute flag_meanings_row2 = "no_climatology_analysis_was_performed less_than_2sigma  greater_than_2sigma_but_less_than_3sigma greater_than_3sigma_but_less_than_4sigma greater_than_4sigma"
	attribute flag_meanings_row3 = "passed_the_constant_value_test failed_the_constant_value_test"
	attribute flag_meanings_row4 = "passed_spike_test falied_spike_test"
	attribute flag_meanings_row5 = "passed_gradient_test falied_gradient_test"
	attribute flag_values_row1 = 0, 1, 4, 9
	attribute flag_values_row2 = 0, 1, 2, 3, 4
	attribute flag_values_row3 = 1, 3
	attribute flag_values_row4 = 1, 4
	attribute flag_values_row5 = 1, 4
	attribute long_name = "quality flag of sea surface temperature secondary level"
	attribute references = (empty)
	attribute row_meanings = "row1=regional/global_range_check row2=climatology_control row3=constant_value_check row4=spike_check row5=gradient_check"
dataset /string1: float32, shape (50)
dataset /time: float64, shape (10650, 1)
	attribute _FillValue = -9999.0
	attribute axis = "T"
	attribute calendar = "julian"
	attribute comment = "Changed the orginal reference time to 1970-1-1"
	attribute long_name = "time"
	attribute standard_name = "time"
	attribute units = "seconds since 1970-01-01 00:00:00 0:00"
dataset /trajectory: string(1), shape (1, 50)
	attribute cf_role = "trajectory_id"
	attribute long_name = "Unique identifier for each feature instance"