netcdf frf/projects/WaveShape/AquatecABS/20170929/FRF-ocean_WaveShape_ABS_Crab20170929_05.nc { dimensions: station_name_length = 46; time = UNLIMITED; // (18000 currently) r = 120; variables: double time(time=18000); :_FillValue = -999.99; // 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 latitude; :_FillValue = -999.99; // double :units = "degrees_north"; :standard_name = "latitude"; :long_name = "Latitude"; :short_name = "latitude"; double longitude; :_FillValue = -999.99; // double :units = "degrees_east"; :standard_name = "longitude"; :long_name = "Longitude"; :short_name = "longitude"; double r(r=120); :_FillValue = -999.99; // double :units = "m"; :short_name = "alongBeamR"; :long_name = "Along Beam Distance"; :coordinates = "time"; :note = "Corrected for speed of sound"; :_ChunkSizes = 120U; // uint char station_name(station_name_length=46); :units = ; :long_name = "station name"; :cf_role = "timeseries_id"; :short_name = "station_name"; :_ChunkSizes = 46U; // uint double ABS1(time=18000, r=120); :_FillValue = -999.99; // double :units = "counts/65536"; :note = "Near field correction applied (Downing et al, 1995) and corrected for water attenuation (Fisher and Simmons, 1977), beam spreading, and system constant."; :short_name = "ABS1MHz"; :long_name = "1 MHz acoustic backscatter amplitude"; :Frequency = 1.0; // double :FrequencyUnits = "MHz"; :Kt = 0.02744; // double :KtNote = "Kt = system constant for this transducer"; :Orientation = "vertical"; :OrientationNote = "Tranducer oriented vertically looking down"; :Elevation = 0.76; // double :ElevationNote = "Elevation (m) measured from ground to transducer when CRAB parked on hard surface. CRAB sank into seabed while on station so actual height above bottom varied."; :TransducerRadius = 0.008999999612569809; // double :TransducerRadiusUnits = "m"; :_ChunkSizes = 18000U, 120U; // uint double ABS2(time=18000, r=120); :_FillValue = -999.99; // double :units = "counts/65536"; :note = "Near field correction applied (Downing et al, 1995) and corrected for water attenuation (Fisher and Simmons, 1977), beam spreading, and system constant."; :short_name = "ABS1MHz"; :long_name = "1 MHz acoustic backscatter amplitude"; :Frequency = 1.0; // double :FrequencyUnits = "MHz"; :Kt = 0.03078; // double :KtNote = "Kt = system constant for this transducer"; :Orientation = "skew"; :OrientationNote = "Transducer aimed askew at approximately 45 deg from vertical toward stern of CRAB. Stern of CRAB faced offshore in all cases except stations 4 and 5 on 11-18-2016."; :Elevation = 0.76; // double :ElevationNote = "Elevation (m) measured from ground to transducer when CRAB parked on hard surface. CRAB sank into seabed while on station so actual height above bottom varied."; :TransducerRadius = 0.008999999612569809; // double :TransducerRadiusUnits = "m"; :_ChunkSizes = 18000U, 120U; // uint double ABS3(time=18000, r=120); :_FillValue = -999.99; // double :units = "counts/65536"; :note = "Near field correction applied (Downing et al, 1995) and corrected for water attenuation (Fisher and Simmons, 1977), beam spreading, and system constant."; :short_name = "ABS2MHz"; :long_name = "2 MHz acoustic backscatter amplitude"; :Frequency = 2.0; // double :FrequencyUnits = "MHz"; :Kt = 0.01273; // double :KtNote = "Kt = system constant for this transducer"; :Orientation = "vertical"; :OrientationNote = "Tranducer oriented vertically looking down"; :Elevation = 0.76; // double :ElevationNote = "Elevation (m) measured from ground to transducer when CRAB parked on hard surface. CRAB sank into seabed while on station so actual height above bottom varied."; :TransducerRadius = 0.004800000227987766; // double :TransducerRadiusUnits = "m"; :_ChunkSizes = 18000U, 120U; // uint double ABS4(time=18000, r=120); :_FillValue = -999.99; // double :units = "counts/65536"; :note = "Near field correction applied (Downing et al, 1995) and corrected for water attenuation (Fisher and Simmons, 1977), beam spreading, and system constant."; :short_name = "ABS4MHz"; :long_name = "4 MHz acoustic backscatter amplitude"; :Frequency = 4.0; // double :FrequencyUnits = "MHz"; :Kt = 0.00984; // double :KtNote = "Kt = system constant for this transducer"; :Orientation = "vertical"; :OrientationNote = "Tranducer oriented vertically looking down"; :Elevation = 0.76; // double :ElevationNote = "Elevation (m) measured from ground to transducer when CRAB parked on hard surface. CRAB sank into seabed while on station so actual height above bottom varied."; :TransducerRadius = 0.0048500001430511475; // double :TransducerRadiusUnits = "m"; :_ChunkSizes = 18000U, 120U; // uint double pressure(time=18000); :_FillValue = -999.99; // double :units = "dbar"; :short_name = "pressure"; :long_name = "pressure"; :note = "Barometric corrected. This instrument produced weird negative pressure values during experiment but seemed normal on bench testing months afterward. Corrected using local pressure and estimated offset of 24.506. Corrected data looks OK but use with caution."; :_ChunkSizes = 18000U; // uint // global attributes: :cdm_data_type = "Station"; :featureType = "timeSeries"; :title = "FRF Wave Shape 6.1, Aquatec Aquascat1000R data"; :summary = "Current and pressure data collected at the USACE Coastal Hydraulics Laboratory (CHL), Field Research Facility (FRF) in Duck, NC. These data were collected in the Atlantic Ocean at numerous stations in the surf zone in Nov 2016, Jan 2017, Apr 2017, Sep 2017, and Oct 2017. Data were collected with a Aquatec Aquascat1000R multifrequency acoustic backscatter profiling sensor mounted on the Coastal Research Amphibious Buggy (CRAB) along with other acoustic and optical sensors. The Aquascat measured acoustic backscatter using 3 frequencies of sound as well as pressure. The CRAB occupied numerous stations near the break point in the surf zone on each field day. Stations were typically occupied for 30 minutes. Data were sampled at 40 to 80 Hz and internally averaged to 5 to 10 Hz for the first 58 minutes of each hour while the CRAB was in the water. A .nc file was created for each station.\n"; :history = "USACE/FRF"; :source = "In situ observations from ABS_Crabmmddyy.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://www.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 Acoustics > Acoustic backscatter, 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\n"; :processing = "post process"; :organization = "U.S. Army Corps of Engineers (USACE), Engineering Research and Development Center (ERDC), Coastal Hydraulics Laboratory (CHL), Observation and Analysis Branch (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 = "2018-09-17"; :date_issued = "2018-09-17"; :project = "USACE/FRF observations"; :id = "FRF-ocean_WaveShape_ABS"; :acknowledgement = "Data are provided by the U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, Duck, NC."; :processing_level = "L1"; :geospatial_vertical_units = "m"; :geospatial_vertical_resolution = 0.0; // double :geospatial_vertical_min = -6.0; // double :geospatial_vertical_max = 1.0; // double :geospatial_vertical_origin = "NAVD88"; :geospatial_vertical_positive = "up"; :geospatial_lat_units = "degrees_north"; :geospatial_lon_units = "degrees_east"; :nomDepth_units = "m"; :sensorHeightAboveBottom = 0.4; // double :manufacturer = "Aquatec"; :model = "Aquascat1000R"; :serialNumber = "910-145"; :comment = "Instrument height above bottom varied from about 0.1 meters to 0.5 meters as CRAB sank into the bottom over time."; :Station = "20170929_05"; :geospatial_lat_min = 36.18549; // double :geospatial_lat_max = 36.18549; // double :geospatial_lon_min = -75.75119; // double :geospatial_lon_max = -75.75119; // double :time_coverage_start = "29-Sep-2017 17:20:00"; :time_coverage_end = "29-Sep-2017 17:49:59"; :deployment_start = "29-Sep-2017 17:20:00"; :deployment_end = "29-Sep-2017 17:49:59"; :nomDepth = 1.5928; // double :nomDepthNote = "Water depth at station calculated from End of Pier water level - Crab surveyed bottom elevation at start of station"; }