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   set  data   graph     files  Fugro Cruise C16185 Line 0973, 75 kHz VMADCP    ?   F   I   M   background (external link) RSS Subscribe GCOOS C16185_075_Line0973_0

The Dataset's Variables and Attributes

Row Type Variable Name Attribute Name Data Type Value
attribute NC_GLOBAL _NCProperties String version=2,netcdf=4.7.4,hdf5=1.12.0,
attribute NC_GLOBAL acknowledgement String Data collection funded by various oil industry operators
attribute NC_GLOBAL cdm_data_type String TrajectoryProfile
attribute NC_GLOBAL cdm_profile_variables String time
attribute NC_GLOBAL cdm_trajectory_variables String trajectory
attribute NC_GLOBAL CODAS_processing_note String
CODAS processing note:
======================

Overview
--------
The CODAS database is a specialized storage format designed for
shipboard ADCP data. "CODAS processing" uses this format to hold
averaged shipboard ADCP velocities and other variables, during the
stages of data processing. The CODAS database stores velocity
profiles relative to the ship as east and north components along with
position, ship speed, heading, and other variables. The netCDF *short*
form contains ocean velocities relative to earth, time, position,
transducer temperature, and ship heading; these are designed to be
"ready for immediate use". The netCDF *long* form is just a dump of
the entire CODAS database. Some variables are no longer used, and all
have names derived from their original CODAS names, dating back to the
late 1980's.

Post-processing
---------------
CODAS post-processing, i.e. that which occurs after the single-ping
profiles have been vector-averaged and loaded into the CODAS database,
includes editing (using automated algorithms and manual tools),
rotation and scaling of the measured velocities, and application of a
time-varying heading correction. Additional algorithms developed more
recently include translation of the GPS positions to the transducer
location, and averaging of ship's speed over the times of valid pings
when Percent Good is reduced. Such post-processing is needed prior to
submission of "processed ADCP data" to JASADCP or other archives.

Full CODAS processing
---------------------
Whenever single-ping data have been recorded, full CODAS processing
provides the best end product.

Full CODAS processing starts with the single-ping velocities in beam
coordinates. Based on the transducer orientation relative to the
hull, the beam velocities are transformed to horizontal, vertical, and
"error velocity" components. Using a reliable heading (typically from
the ship's gyro compass), the velocities in ship coordinates are
rotated into earth coordinates.

Pings are grouped into an "ensemble" (usually 2-5 minutes duration)
and undergo a suite of automated editing algorithms (removal of
acoustic interference; identification of the bottom; editing based on
thresholds; and specialized editing that targets CTD wire interference
and "weak, biased profiles". The ensemble of single-ping velocities
is then averaged using an iterative reference layer averaging scheme.
Each ensemble is approximated as a single function of depth, with a
zero-average over a reference layer plus a reference layer velocity
for each ping. Adding the average of the single-ping reference layer
velocities to the function of depth yields the ensemble-average
velocity profile. These averaged profiles, along with ancillary
measurements, are written to disk, and subsequently loaded into the
CODAS database. Everything after this stage is "post-processing".

note (time):
------------
Time is stored in the database using UTC Year, Month, Day, Hour,
Minute, Seconds. Floating point time "Decimal Day" is the floating
point interval in days since the start of the year, usually the year
of the first day of the cruise.


note (heading):
---------------
CODAS processing uses heading from a reliable device, and (if
available) uses a time-dependent correction by an accurate heading
device. The reliable heading device is typically a gyro compass (for
example, the Bridge gyro). Accurate heading devices can be POSMV,
Seapath, Phins, Hydrins, MAHRS, or various Ashtech devices; this
varies with the technology of the time. It is always confusing to
keep track of the sign of the heading correction. Headings are written
degrees, positive clockwise. setting up some variables:

X = transducer angle (CONFIG1_heading_bias)
positive clockwise (beam 3 angle relative to ship)
G = Reliable heading (gyrocompass)
A = Accurate heading
dh = G - A = time-dependent heading correction (ANCIL2_watrk_hd_misalign)

Rotation of the measured velocities into the correct coordinate system
amounts to (u+i*v)*(exp(i*theta)) where theta is the sum of the
corrected heading and the transducer angle.

theta = X + (G - dh) = X + G - dh


Watertrack and Bottomtrack calibrations give an indication of the
residual angle offset to apply, for example if mean and median of the
phase are all 0.5 (then R=0.5). Using the "rotate" command,
the value of R is added to "ANCIL2_watrk_hd_misalign".

new_dh = dh + R

Therefore the total angle used in rotation is

new_theta = X + G - dh_new
= X + G - (dh + R)
= (X - R) + (G - dh)

The new estimate of the transducer angle is: X - R
ANCIL2_watrk_hd_misalign contains: dh + R

====================================================

Profile flags
-------------
Profile editing flags are provided for each depth cell:

binary decimal below Percent
value value bottom Good bin
-------+----------+--------+----------+-------+
000 0
001 1 bad
010 2 bad
011 3 bad bad
100 4 bad
101 5 bad bad
110 6 bad bad
111 7 bad bad bad
-------+----------+--------+----------+-------+
attribute NC_GLOBAL CODAS_variables String
Variables in this CODAS short-form Netcdf file are intended for most end-user
scientific analysis and display purposes. For additional information see
the CODAS_processing_note global attribute and the attributes of each
of the variables.


============= =================================================================
time Time at the end of the ensemble, days from start of year.
lon, lat Longitude, Latitude from GPS at the end of the ensemble.
u,v Ocean zonal and meridional velocity component profiles.
uship, vship Zonal and meridional velocity components of the ship.
heading Mean ship heading during the ensemble.
depth Bin centers in nominal meters (no sound speed profile correction).
tr_temp ADCP transducer temperature.
pg Percent Good pings for u, v averaging after editing.
pflag Profile Flags based on editing, used to mask u, v.
amp Received signal strength in ADCP-specific units; no correction
for spreading or attenuation.
============= =================================================================

attribute NC_GLOBAL contributor_name String RPS
attribute NC_GLOBAL contributor_role String editor
attribute NC_GLOBAL contributor_role_vocabulary String https://vocab.nerc.ac.uk/collection/G04/current/ (external link)
attribute NC_GLOBAL Conventions String CF-1.6, ACDD-1.3, IOOS Metadata Profile Version 1.2, COARDS
attribute NC_GLOBAL creator_address String 6100 Hillcroft Avenue
attribute NC_GLOBAL creator_city String Houston
attribute NC_GLOBAL creator_country String USA
attribute NC_GLOBAL creator_email String metoceansupport at fugro.com
attribute NC_GLOBAL creator_institution String Fugro Inc
attribute NC_GLOBAL creator_name String Rosemary Smith
attribute NC_GLOBAL creator_phone String 713-369-5600
attribute NC_GLOBAL creator_postalcode String 77081
attribute NC_GLOBAL creator_sector String industry
attribute NC_GLOBAL creator_state String Texas
attribute NC_GLOBAL creator_type String institution
attribute NC_GLOBAL creator_url String https://www.fugro.com/ (external link)
attribute NC_GLOBAL cruise_id String Fugro_wh75
attribute NC_GLOBAL date_created String 21-11-23T11:44:24Z
attribute NC_GLOBAL description String Shipboard ADCP velocity profiles from Fugro_wh75 using instrument wh75
attribute NC_GLOBAL Easternmost_Easting double -89.74283333333335
attribute NC_GLOBAL featureType String TrajectoryProfile
attribute NC_GLOBAL geospatial_bounds String LINESTRING (-90.06612777777775 27.03693888888889, -89.74283333333335 27.307725)
attribute NC_GLOBAL geospatial_bounds_crs String EPSG:4326
attribute NC_GLOBAL geospatial_bounds_vertical_crs String EPSG:5703
attribute NC_GLOBAL geospatial_lat_max double 27.307725
attribute NC_GLOBAL geospatial_lat_min double 27.03693888888889
attribute NC_GLOBAL geospatial_lat_units String degrees_north
attribute NC_GLOBAL geospatial_lon_max double -89.74283333333335
attribute NC_GLOBAL geospatial_lon_min double -90.06612777777775
attribute NC_GLOBAL geospatial_lon_units String degrees_east
attribute NC_GLOBAL geospatial_vertical_max double 651.53
attribute NC_GLOBAL geospatial_vertical_min double 27.53
attribute NC_GLOBAL geospatial_vertical_positive String down
attribute NC_GLOBAL geospatial_vertical_units String m
attribute NC_GLOBAL hg_changeset String 2924:48293b7d29a9
attribute NC_GLOBAL history String Created: 2019-07-15 17:47:33 UTC
attribute NC_GLOBAL id String C16185_075_Line0973_0
attribute NC_GLOBAL infoUrl String ADD ME
attribute NC_GLOBAL institution String GCOOS
attribute NC_GLOBAL instrument String In Situ/Laboratory Instruments > Profilers/Sounders > Acoustic Sounders > ADCP > Acoustic Doppler Current Profiler
attribute NC_GLOBAL keywords String acoustic, adcp, bins, bsee, circulation, coastal, crs, current, currents, data, depth, dir, direction, direction_of_sea_water_velocity, distance, doppler, drilling, Earth Science > Oceans > Ocean Circulation > Ocean Currents, Earth Science > Oceans > Ocean Temperature > Water Temperature, east, eastward, eastward_sea_water_velocity, gcoos, gulf, identifier, instrument, kika, latitude, longitude, mexico, north, northward, northward_sea_water_velocity, observing, ocean, oceans, platform, platform/ocean, profile, profile_id, profiler, sample, sea, sea_water_speed, sea_water_temperature, seawater, series, speed, stations, stations/drilling, surface, system, temperature, time, time series, towards, upward, upward_sea_water_velocity, velocity, vert, water
attribute NC_GLOBAL keywords_vocabulary String GCMD Science Keywords
attribute NC_GLOBAL license String These data may be redistributed and used without restriction.
attribute NC_GLOBAL naming_authority String edu.tamucc.gulfhub
attribute NC_GLOBAL Northernmost_Northing double 27.307725
attribute NC_GLOBAL platform String ship
attribute NC_GLOBAL platform_vocabulary String https://mmisw.org/ont/ioos/platform (external link)
attribute NC_GLOBAL processing_level String QA'ed and checked by Oceanographer
attribute NC_GLOBAL program String Oil and Gas Loop Current VMADCP Program
attribute NC_GLOBAL project String O&G LC VMADCP Program
attribute NC_GLOBAL publisher_address String 6300 Ocean Drive, Unit 5869
attribute NC_GLOBAL publisher_city String Corpus Christi
attribute NC_GLOBAL publisher_country String USA
attribute NC_GLOBAL publisher_email String info at gcoos.org
attribute NC_GLOBAL publisher_institution String Harte Research Institute, Texas A&M University Corpus Christi
attribute NC_GLOBAL publisher_name String Gulf of Mexico Coastal Ocean Observing System (GCOOS)
attribute NC_GLOBAL publisher_phone String (361) 825 3454
attribute NC_GLOBAL publisher_postalcode String 78412
attribute NC_GLOBAL publisher_state String Texas
attribute NC_GLOBAL publisher_type String group
attribute NC_GLOBAL publisher_url String https://gcoos.org (external link)
attribute NC_GLOBAL software String pycurrents
attribute NC_GLOBAL sonar String wh75
attribute NC_GLOBAL source String Current profiler
attribute NC_GLOBAL sourceUrl String (local files)
attribute NC_GLOBAL Southernmost_Northing double 27.03693888888889
attribute NC_GLOBAL standard_name_vocabulary String CF Standard Name Table v67
attribute NC_GLOBAL subsetVariables String time, longitude, latitude, depth, u, v
attribute NC_GLOBAL summary String Program of vessel mount ADCP measurements comprising a combination of 300kHz and 75kHz ADCP data collected in the vicinity of the Loop Current and drilling blocks between 2004 and 2007.
attribute NC_GLOBAL time_coverage_duration String P0Y0M0DT5H20M54S
attribute NC_GLOBAL time_coverage_end String 2006-05-10T16:35:02Z
attribute NC_GLOBAL time_coverage_resolution String P0Y0M0DT0H4M59S
attribute NC_GLOBAL time_coverage_start String 2006-05-10T11:14:08Z
attribute NC_GLOBAL title String Fugro Cruise C16185 Line 0973, 75 kHz VMADCP
attribute NC_GLOBAL Westernmost_Easting double -90.06612777777775
attribute NC_GLOBAL yearbase int 2006
variable trajectory   int  
attribute trajectory _FillValue int -9999
attribute trajectory actual_range int 1219029256, 1219029256
attribute trajectory cf_role String trajectory_id
attribute trajectory ioos_category String Identifier
attribute trajectory standard_name String trajectory_id
variable time   double  
attribute time _CoordinateAxisType String Time
attribute time actual_range double 1.147259648E9, 1.147278902E9
attribute time axis String T
attribute time C_format String %12.5f
attribute time cf_role String profile_id
attribute time ioos_category String Time
attribute time long_name String Time
attribute time standard_name String time
attribute time time_origin String 01-JAN-1970 00:00:00
attribute time units String seconds since 1970-01-01T00:00:00Z
variable longitude   double  
attribute longitude _CoordinateAxisType String Lon
attribute longitude _FillValue double 1.0E38
attribute longitude actual_range double -90.06612777777775, -89.74283333333335
attribute longitude axis String X
attribute longitude C_format String %9.4f
attribute longitude ioos_category String Location
attribute longitude long_name String Longitude
attribute longitude missing_value double 1.0E38
attribute longitude standard_name String longitude
attribute longitude units String degrees_east
variable latitude   double  
attribute latitude _CoordinateAxisType String Lat
attribute latitude _FillValue double 1.0E38
attribute latitude actual_range double 27.03693888888889, 27.307725
attribute latitude axis String Y
attribute latitude C_format String %9.4f
attribute latitude ioos_category String Location
attribute latitude long_name String Latitude
attribute latitude missing_value double 1.0E38
attribute latitude standard_name String latitude
attribute latitude units String degrees_north
variable depth   float  
attribute depth _CoordinateAxisType String Height
attribute depth _CoordinateZisPositive String down
attribute depth _FillValue float 1.0E38
attribute depth actual_range float 27.53, 651.53
attribute depth axis String Z
attribute depth C_format String %8.2f
attribute depth coverage_content_type String physicalMeasurement
attribute depth ioos_category String Location
attribute depth long_name String Depth
attribute depth missing_value float 1.0E38
attribute depth positive String down
attribute depth postitive String down
attribute depth standard_name String depth
attribute depth units String m
variable u   float  
attribute u _FillValue float 1.0E38
attribute u actual_range float -0.013073444, 0.9552909
attribute u C_format String %7.2f
attribute u coverage_content_type String physicalMeasurement
attribute u ioos_category String Currents
attribute u long_name String Zonal velocity component
attribute u missing_value float 1.0E38
attribute u standard_name String eastward_sea_water_velocity
attribute u units String meter second-1
variable v   float  
attribute v _FillValue float 1.0E38
attribute v actual_range float -0.61686933, 0.061612368
attribute v C_format String %7.2f
attribute v coverage_content_type String physicalMeasurement
attribute v ioos_category String Currents
attribute v long_name String Meridional velocity component
attribute v missing_value float 1.0E38
attribute v standard_name String northward_sea_water_velocity
attribute v units String meter second-1
variable amp   short  
attribute amp _FillValue short 32767
attribute amp actual_range short 74, 207
attribute amp C_format String %d
attribute amp coverage_content_type String physicalMeasurement
attribute amp ioos_category String Identifier
attribute amp long_name String Received signal strength
attribute amp missing_value short 32767
variable pg   byte  
attribute pg _FillValue byte -1
attribute pg actual_range byte 93, 100
attribute pg C_format String %d
attribute pg coverage_content_type String qualityInformation
attribute pg ioos_category String Unknown
attribute pg long_name String Percent Good
attribute pg missing_value byte -1
variable pflag   byte  
attribute pflag actual_range byte 0, 1
attribute pflag C_format String %d
attribute pflag coverage_content_type String qualityInformation
attribute pflag ioos_category String Identifier
attribute pflag long_name String Editing flags
variable heading   float  
attribute heading _FillValue float 1.0E38
attribute heading actual_range float 300.72, 327.58
attribute heading C_format String %6.1f
attribute heading coverage_content_type String auxiliaryInformation
attribute heading ioos_category String Unknown
attribute heading long_name String Ship heading
attribute heading missing_value float 1.0E38
attribute heading units String degrees
variable tr_temp   float  
attribute tr_temp _FillValue float 1.0E38
attribute tr_temp actual_range float 26.09, 26.38
attribute tr_temp C_format String %4.1f
attribute tr_temp coverage_content_type String auxiliaryInformation
attribute tr_temp ioos_category String Unknown
attribute tr_temp long_name String some temperature
attribute tr_temp missing_value float 1.0E38
attribute tr_temp units String Celsius
variable num_pings   short  
attribute num_pings actual_range short 24, 135
attribute num_pings C_format String %d
attribute num_pings coverage_content_type String auxiliaryInformation
attribute num_pings ioos_category String Identifier
attribute num_pings long_name String Number of pings averaged per ensemble
variable uship   float  
attribute uship _FillValue float 1.0E38
attribute uship actual_range float -1.959413, -0.7935954
attribute uship C_format String %9.4f
attribute uship coverage_content_type String physicalMeasurement
attribute uship ioos_category String Currents
attribute uship long_name String Ship Velocity U
attribute uship missing_value float 1.0E38
attribute uship units String meter second-1
variable vship   float  
attribute vship _FillValue float 1.0E38
attribute vship actual_range float 1.21156, 2.352931
attribute vship C_format String %9.4f
attribute vship coverage_content_type String physicalMeasurement
attribute vship ioos_category String Currents
attribute vship long_name String Ship Velocity V
attribute vship missing_value float 1.0E38
attribute vship units String meter second-1

The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.


 
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