Metadata Report for BODC Series Reference Number 1624092


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Teledyne RDI Workhorse Sentinel-600 ADCP  current profilers
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator Dr Matt Palmer
Originating Organization Proudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Processing Status banked
Project(s) Oceans 2025 Theme 10 SO11
 

Data Identifiers

Originator's Identifier BB05806.01090
BODC Series Reference 1624092
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2010-03-17 13:25
End Time (yyyy-mm-dd hh:mm) 2010-04-28 10:55
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 53.53267 N ( 53° 32.0' N )
Longitude 3.35833 W ( 3° 21.5' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 3.6 m
Maximum Sensor Depth 24.55 m
Minimum Sensor Height 2.64 m
Maximum Sensor Height 23.6 m
Sea Floor Depth 27.2 m
Sensor Distribution Sensor fixed, measurements made at fixed depths - The sensor is at a fixed depth, but measurements are made remotely from the sensor over a range of depths (e.g. ADCP measurements)
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODE Rank Units Short Title Title
HBINAA01 0 Metres BinHeight Height above bed (ADCP bin) in the water body
AADYAA01 1 Days Date(Loch_Day) Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time(Day_Fract) Time (time between 00:00 UT and timestamp)
ASLVMWHA 1 Metres SL_MWH_ADCP Surface elevation (Mean Water Height) of the water body by acoustic doppler current profiler (ADCP)
LCEWAP01 2 Centimetres per second CurrVelE_ADCP Eastward current velocity (Eulerian) in the water body by moored acoustic doppler current profiler (ADCP)
LCNSAP01 2 Centimetres per second CurrVelN_ADCP Northward current velocity (Eulerian) in the water body by moored acoustic doppler current profiler (ADCP)
LERRAP01 2 Centimetres per second ADCPER Current velocity error in the water body by moored acoustic doppler current profiler (ADCP)
LRZAAP01 2 Centimetres per second ADCPVC Upward current velocity in the water body by moored acoustic doppler current profiler (ADCP)
 

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database

Originator's quality control comments for PD05_10 COBS moorings

Data supplied to BODC were accompanied by data quality notes from the Originator that detailed observations made when the data were processed and subsequent processing decisions. A summary of these notes have been provided in the tables below.

Site A

Rig#1089

Instrument Serial number Instrument depth Data quality comments
Sea-Bird MicroCAT 04966 5 m None.
Star-Oddi minilogger 02842 7.5 m Comparisons performed against CTD data found an offset with a minimum value of -0.1447°C, however this was reduced by 0.09°C after comparing these data to data recorded by both Sea-Bird MicroCATs present at this site. An overall offset correction of +0.0547°C has been applied to these data.
Sea-Bird MicroCAT 05434 10 m There was a good match between CTD temperature and conductivity and the data recorded by this instrument at mooring deployment, however temperature was out by 0.1°C at mooring recovery.
Star-Oddi minilogger 02843 15 m A temperature offset of +0.03°C was found when these data were compared with the data recorded by the other instruments present at this site. An offset correction of -0.03°C has been applied to these data

Rig#1090


Instrument Serial number Instrument depth Data quality comments
Sea-Bird 16+ SEACAT fitted with Seapoint Turbidity Meter #10537 04738 Located on seabed Comparisons performed against other instruments present at this site found a salinity offset of -0.05. An offset correction of +0.05 has been applied to these data.
Teledyne RDI 600 kHz ADCP 5806 Located on seabed To correct for the magnetic declination (difference between magnetic north and true north) latitude values were changed by -3.2335°. All latitude values were modified by +4.2925° to correct for the compass error.

Site B

Rig#1091

Instrument Serial number Instrument depth Data quality comments
Sea-Bird MicroCAT 05792 5 m Comparisons against CTD data found a consistent temperature offset of 0.01°C. There was a good match between CTD conductivity and the CTD data recorded by this instrument at mooring deployment, however conductivity was out by 0.01 S m-1 at mooring recovery.
Star-Oddi minilogger 02844 7.5 m A temperature offset of -0.04°C was found when these data were compared with the data recorded by the Sea-Bird MicroCATs also present at this site. An offset correction of +0.04°C has been applied to these data.
Sea-Bird MicroCAT 04998 10 m None.
Star-Oddi minilogger 02852 15 m A temperature offset of -0.04°C was found when these data were compared with the data recorded by the Sea-Bird MicroCATs also present at this site. An offset correction of +0.04°C has been applied to these data.

Rig#1092


Instrument Serial number Instrument depth Data quality comments
Sea-Bird 16+ SEACAT fitted with Seapoint Turbidity Meter #10471 04736 Located on seabed None.
Teledyne RDI 600 kHz ADCP 2390 Located on seabed To correct for the magnetic declination (difference between magnetic north and true north) latitude values were changed by -3.3592°. All latitude values were modified by -0.58093° to correct for the compass error.After this instrument was moved from the old site B location to the new site B location the number of bins was not correctly adjusted to take into account the greater water depth at the new location, resulting in a loss of data from the near-surface bins.

Data Access Policy

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."


Narrative Documents

Teledyne RDI Workhorse Sentinel 600 kHz Acoustic Doppler Current Profiler (ADCP)

The Workhorse Sentinel is a self-contained ADCP that can be used either on a mooring or mounted in the hull of a moving vessel. Its 4-beam design provides a redundant data source (in case of a blocked or damaged beam), an independent data quality measure (error velocity) and reduces the variance in data, thereby improving data reliability, quality and accuracy.

Real-time data can be transmitted to shore via a cable link or acoustic modem or they can be stored internally. Sensors for bottom tracking, pressure and directional wave measurements can be added to the instrument and a special casing is available for deeper applications.

Specifications

Typical range 50 m
Number of depth cells 1 to 128
Typical ping rate 2 Hz
Standard depth rating 200 to 6000 m
Beam angle 20 °
Echo intensity profile
Dynamic range 80 dB
Precision ± 1.5 dB
Velocity
Accuracy 0.3% of the water velocity relative to the ADCP ± 0.3 cm s -1
Resolution 0.1 cm s -1
Range

± 5 m s -1 (default)

± 20 m s -1 (maximum)

Vertical resolution Range / Std Dev
for 0.5 m 39 m / 12.9 cm s -1
for 1 m 43 m / 6.1 cm s -1
for 2 m 47 m / 3.0 cm s -1
for 4 m 52 m / 2.0 cm s -1
Long Range mode
Range 70 m
Depth cell size 4 m
Std Deviation 4.2 cm s -1
Temperature
Operating temp. -5 to 45 °C
Precision ± 0.4 °C
Resolution 0.01 °C
Tilt
Range ± 15 °
Accuracy ± 0.5 °
Precision ± 0.5 °
Resolution 0.01 °
Compass
Accuracy ± 2 °
Resolution 0.01 °
Maximum tilt ± 15 °
Precision ± 0.5 °

Further details can be found in the manufacturer's specification sheet .

BODC Processing document for Coastal Observatory moored ADCP data

The data arrived at BODC as 117 ASCII format .dat files representing moored ADCP data recorded at the Coastal Observatory sites 1(9), 20 and 21 between 07 August 2002 and 20 September 2011. Following standard BODC procedure the files were reformatted into BODC standard internal format using an internal transfer function. The following table shows how the originator's variables were mapped to the appropriate BODC parameter codes:

Originator's variable Units Description BODC parameter code Units Comments
Sea surface height m Surface elevation (Mean Water Height) of the water body by acoustic doppler current profiler (ADCP) ASLVMWHA Metres -
East cm/s Eastward current velocity (Eulerian) in the water body by moored acoustic doppler current profiler (ADCP) LCEWAP01 cm s -1 -
North cm/s Northward current velocity (Eulerian) in the water body by moored acoustic doppler current profiler (ADCP) LCNSAP01 cm s -1 -
Vertical cm/s Upward current velocity in the water body by moored acoustic doppler current profiler (ADCP) LRZAAP01 cm s -1 -
Error cm/s Current velocity error in the water body by moored acoustic doppler current profiler (ADCP) LERRAP01 cm s -1 -
Height from sea bed m Height above bed (ADCP bin) in the water body HBINAA01 Metres -

The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, missing data by both setting the data to an appropriate value and setting the quality control flag.

COBS RDI Teledyne 600 kHz ADCP Data Processing

Sampling Strategy

Two mooring sites were maintained for the duration of the Liverpool Bay Coastal Observatory project. Moored instruments present at Site A (also known as Site 1/9) through the entire data collection phase of the observatory. From 05 April 2005 (Cruise PD11_05) moorings were also present at an additional Site B. From April 2005 until December 2009 mooring Site B was located at Coastal Observatory Station 20. The moorings were moved to Station 21 from January 2010, where they remained until the end of the observatory.

Originator's Processing

The raw ADCP data were processed using the standard RDI software bblist which resulted in the creation of two files, the first containing the current velocities separated by bin depth and an auxiliary file containing the variables heading, pitch, roll, temperature and pressure. The variables present in the auxiliary files were only used for quality control purposes with the exception of pressure, which was used to calculate sea surface height taking into account the latitude and the height of the transducer head above the seabed, which was estimated to be 0.7 m. Sea surface height and the current velocity data were then combined into one file.

Before the data were supplied to BODC, some quality control procedures were performed by the Data Originator. First the Originator corrected the latitude values to take into account the difference between magnetic north and true north (magnetic declination). The Originator also corrected the latitude values for compass error caused by localised magnetic fields such as the ADCP frame and battery, using HF radar data recorded by two HF radars located at Abergele and Formby as a reference. Once compass errors for all ADCP series recorded at Site A had been calculated, a mean of all errors was taken. As the ADCP compass error is a random error, the expected mean of all errors is approximately 0°, however the Originator found that the actual mean compass error was approximately 5.3°. All compass errors were therefore modified by 5.3°. The compass error values given in the Originator's data processing documents have taken this adjustment into account.

The bins recorded above the sea surface were then converted to absent data indicators by the Data Originator. If there were any problems with the pressure data recorded by the ADCP, then data from another instrument attached to the same frame was used instead. If no pressure records were available, then backscatter intensity was used to calculate the sea surface. The top three bins have been removed in all series to remove noise in these data caused by side lobe contamination. A more detailed explanation of all of the quality control procedures performed before the data were submitted to BODC can be found in the Originator's ADCP quality control methodology document.

Prior to cruise PD33_08 the data originator had been correcting the mid-water current velocities to account for contamination caused by the recovery line attached to the ADCP lander frame. The mooring design was changed from PD33_08, and this redesign successfully eradicated the beam contamination issues that had affected previous deployments. Therefore, no three-beam correction has been applied to these data. This issue is explained in detail in the originator's ADCP correction report , however as previously stated no three-beam correction was applied to these data.

Finally a visual inspection of the data was carried out to find any obvious errors which had not been corrected by the previous quality control checks.


Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 11: Liverpool Bay and Irish Sea Coastal Observatory

Sustained, systematic observations of the ocean and continental shelf seas at appropriate time and space scales allied to numerical models are key to understanding and prediction. In shelf seas these observations address issues as fundamental as 'what is the capacity of shelf seas to absorb change?' encompassing the impacts of climate change, biological productivity and diversity, sustainable management, pollution and public health, safety at sea and extreme events. Advancing understanding of coastal processes to use and manage these resources better is challenging; important controlling processes occur over a broad range of spatial and temporal scales which cannot be simultaneously studied solely with satellite or ship-based platforms.

Considerable effort has been spent by the Proudman Oceangraphic Laboratory (POL) in the years 2001 - 2006 in setting up an integrated observational and now-cast modelling system in Liverpool Bay (see Figure), with the recent POL review stating the observatory was seen as a leader in its field and a unique 'selling' point of the laboratory. Cost benefit analysis (IACMST, 2004) shows that benefits really start to accrue after 10 years. In 2007 - 2012 exploitation of (i) the time series being acquired, (ii) the model-data synthesis and (iii) the increasingly available quantities of real-time data (e.g. river flows) can be carried out through Sustained Observation Activity (SO) 11, to provide an integrated assessment and short term forecasts of the coastal ocean state.

BODC image

Overall Aims and Purpose of SO 11

Measurement and Modelling Activities

More detailed information on this Work Package is available at pages 32 - 35 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/

References:

IACMST., 2004. The Economics of Sustained Marine Measurements. IACMST Information Document, N0.11, Southampton: IACMST, 96 pp


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2010-03-17
End Date (yyyy-mm-dd) 2010-04-28
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG#1090
Platform Categorysubsurface mooring

Proudman Oceanographic Laboratory Rig#1090

Deployment and Recovery

The rig was deployed at Coastal Observatory Site A on 17 March 2010 during RV Prince Madog cruise PD05/10 and recovered on 28 April 2010 during RV Prince Madog cruise PD10/10.

Rig Position 53.533°, -3.358°
Water Depth 27.2 m
Deployed 17 March 2010 13:20 UTC
Recovered 28 April 2010 12:37 UTC
No. of days 41.9

Rig Description

This rig is a bottom frame comprising of the following instruments 0.5 m above the seabed: RDI Acoustic Doppler Current Profiler (ADCP); Sea-Bird 16plus; an additional Sea-Bird 16plus providing logging and power for an Aanderaa oxygen optode; and a SonTek ADV (Acoustic Doppler Velocimeter).The frame was fitted with a fizz link, a spooler with 50 m of rope for recovery of the ballast weight and two Benthos releases.


Instrument Serial Number Parameters Measured Comments
RDI 600 kHz Waves ADCP 5806 Horizontal current velocity components. Vertical current velocity components. Sea surface height Sound velocity calculated from temperature, depth and salinity of 32. Fitted with a pressure sensor; hourly wave recording enabled.
Sea-Bird 16plus
V RS-485
4490 Temperature
Conductivity
Oxygen concentration
Internal temperature of optode
Includes Aanderaa Optode S/N 674. us. No data from this instrument has been provided to BODC.
Sea-Bird 16plus
V RS-485
4738 Temperature
Conductivity
Oxygen concentration
Internal temperature of optode
SeaPoint turbidity sensor (serial number 10538) taped to roll bar; set up to 0-125 FTU range

For more information about the instruments please see the cruise report for PD05/10.

Other Series linked to this Data Activity - 1641452

Cruise

Cruise Name PD05/10
Departure Date 2010-03-17
Arrival Date 2010-03-17
Principal Scientist(s)Phil J Knight (Proudman Oceanographic Laboratory)
Ship RV Prince Madog

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameCOA
CategoryOffshore area
Latitude53° 31.51' N
Longitude3° 23.00' W
Water depth below MSL26.0 m

Liverpool Bay Coastal Observatory Mooring Site A (COA/Site 1/Site 9)

This station is the main mooring site for the Proudman Oceanographic Laboratory (POL) Liverpool Bay Coastal Observatory and was first occupied in 2002. It is also known both as Coastal Observatory Site 1 and Site 9. POL perform two main types of activities at this station: they deploy moorings; and in addition, they take CTD profiles during each site visit. The station lies within a box of mean water depth 22.5 m with the following coordinates:

Box Corner Latitude (+ve North) Longitude (+ve East)
North-west corner 53.54097 -3.42958
South-east corner 53.50945 -3.33714

The position of this station relative to the other POL Coastal Observatory sites can be seen from the figure below.

BODC image

Mooring Deployment History

2011

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, OBS, OXY 1117, 1121, 1125, 1127, 1130, 1132, January - November
SmartBuoy CTD x 2, AC-S, CT x 2, FL x 3, OBS x 2, PAR x 2, WMS, NAS, OXY, T x 2 1116, 1120, 1124 January - November

2010

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 1086, 1090, 1094, 1098, 1102, 1106, 1109 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD, T 1085, 1089, 1093, 1097, 1101, 1105, 1108, 1112 January - December

2009

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 1055, 1062, 1067, 1071, 1074, 1078, 1082 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD, T 1054, 1061, 1066, 1070, 1073, 1077, 1081 January - December

2008

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 1024, 1028, 1032, 1036, 1041, 1044, 1047, 1051 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD, T LB1_047/1023, LB1_048/1027, LB1_049/1031, LB1_050/1035, 1040, 1043, LB1_053/1050 January - December

2007

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 990, 997, 1001, 1005, 1010, 1014, 1017, 1021 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD, T LB1_039/989, LB1_040/996, LB1_041/1000, LB1_042/1004, LB1_043/1009, LB1_044/1013, LB1_045/1016, LB1_046/1020 January - December

2006

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 951, 962, 966, 970, 974, 978, 982, 986 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD 958, 961, 965, 969, 973, 977, LB1_037/981, LB1_038/985 January - December

2005

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CT 913, 914, 921, 925, 929, 933, 938, 942, 945, 949 January - December
SmartBuoy CT, FL, OBS, PAR, WMS, NAS, OXY 912, 920, 924, 928, 932, 937, LB1_028/941, LB1_029/944, LB1_030/948 January - December
Frame with telemetry buoy ADCP 914 March - April

2004

Rig Type Typical Instruments Rig IDs Comment
Frame BPR, ADCP, TR, CT 890, 892, 893, 896, 898, 900, 902, 904, 907, 908, 910, 911 January - December
SmartBuoy CT, FL, OBS, PAR, WMS, NAS 889, 891, 895, 897, 899, 901, 903, 906, 909 January - December
Frame with telemetry buoy ADCP 893, 908, 911 April - May, October - December

2003

Rig Type Instruments Rig IDs Comment
Frame BPR, ADCP, TR, CT 861, 864, 866, 869, 872, 878, 880, 883, 885, 887, 888 January - December
SmartBuoy CT, FL, OBS, PAR, WMS, NAS 863, 865, 867, 870, 871, 877, 879, 882, 884, 886 January - December

2002

Rig Type Instruments Rig IDs Comment
Frame BPR, ADCP, TR, CT 851, 854, 856, 858 August - December
Line mooring CT x 3 853, 855 August - November
SmartBuoy CT, FL, OBS, PAR, WMS, NAS 857, 860 November - December

2001

Rig Type Instruments Rig IDs Comment
Frame ADCP, OBS 838, 839, 840, 841, 843, 844, 845, 846, 848, 849 September

CTD Sampling History

Year Number of Cruises Total Casts per year
2011 6 116 including a 46 cast tidal cycle from 2011-04-18 to 2011-04-19 and a 51 cast tidal cycle station from 2011-07-27 to 2011-07-28
2010 8 71 including a 52 cast tidal cycle station from 2010-04-28 to 2010-04-29
2009 7 21
2008 9 75 including a 54 cast tidal cycle station from 2008-05-13 to 2008-05-14
2007 8 71 including a 51 cast tidal cycle station from 2007-05-15 to 2007-05-16
2006 9 72 including a 53 cast tidal cycle station from 2006-05-09 to 2006-05-10
2005 9 41 including a 22 cast tidal cycle station from 2005-04-05 to 2005-04-06
2004 9 77 including a 54 cast tidal cycle station from 2004-05-11 to 2004-05-12
2003 10 28
2002 4 13

The CTD instrument package for these cruises was a Sea-Bird 911plus, with beam transmissometer, fluorometer, LICOR PAR sensor, LISST-25, and oxygen sensor.

Key

AC-S = Absorption and attenuation spectrophotometer
ADCP = Acoustic Doppler Current Profiler
ADV = Acoustic Doppler Velocimeter
BD = Bacterial degradation experiment
BPR = Bottom Pressure Recorder
CT = Conductivity and temperature logger
CTD = Conductivity, temperature, depth sensor
FL = Fluorometer
NAS = in-situ nutrient analyser
OBS = Optical Backscatter Turbidity meter
OXY = Oxygen sensor
PAR = PAR sensor
T = Temperature logger
TR = Transmissometer
WMS = Automatic water sampler

Other Series linked to this Fixed Station for this cruise - 1038290 1038308 1075430 1075859 1076003 1076200 1076341 1076445 1076550 1076783 1641403 1641427 1641452 1641464 1641476

Other Cruises linked to this Fixed Station (with the number of series) - CO 01/12 (5) PD01/08 (17) PD01/11 (14) PD02/03 (10) PD02/05 (11) PD02/07 (15) PD02/09B (17) PD02/10 (15) PD04/06 (1) PD06/04 (12) PD06/07 (16) PD07/08 (14) PD07/11 (17) PD09/06 (11) PD09/07 (64) PD09/08 (16) PD10/03 (9) PD10/10 (14) PD11/04B (13) PD11/05 (9) PD11/11 (57) PD12/05 (2) PD12/09 (16) PD13/07 (14) PD14/08 (67) PD16/06 (9) PD16/07 (15) PD17/03 (12) PD17/10 (15) PD18/04 (13) PD18/05 (11) PD18/09 (17) PD19/08 (2) PD20/02 (7) PD20/06 (9) PD20/07 (17) PD21/05 (10) PD21/10 (15) PD21/11 (9) PD22/04 (13) PD22/06 (9) PD23/03A (10) PD23/07 (15) PD23/08 (13) PD24/02 (2) PD24/09 (17) PD25/03B (12) PD25/05 (11) PD25/06 (9) PD25/11 (7) PD27/07 (17) PD29/04 (12) PD29/06 (9) PD29/08 (14) PD29/10 (17) PD30/05 (10) PD31/02 (11) PD31/03 (12) PD32/04 (12) PD33/08 (5) PD33/09 (16) PD34/03 (12) PD34/05 (10) PD35/02 (11) PD35/06 (14) PD36/10 (16) PD37/06 (14) PD37/08 (18) PD38/03 (13) PD38/04 (12) PD38/09 (16) PD41/05 (11) PD43/11 (11) PD44/03 (7) PD47/09 (15) PD48/03 (5) PD48/04 (8) PD48/05 (10) PD49/10 (14) PD52/04 (8)


BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
Blank Unqualified
< Below detection limit
> In excess of quoted value
A Taxonomic flag for affinis (aff.)
B Beginning of CTD Down/Up Cast
C Taxonomic flag for confer (cf.)
D Thermometric depth
E End of CTD Down/Up Cast
G Non-taxonomic biological characteristic uncertainty
H Extrapolated value
I Taxonomic flag for single species (sp.)
K Improbable value - unknown quality control source
L Improbable value - originator's quality control
M Improbable value - BODC quality control
N Null value
O Improbable value - user quality control
P Trace/calm
Q Indeterminate
R Replacement value
S Estimated value
T Interpolated value
U Uncalibrated
W Control value
X Excessive difference

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
0 no quality control
1 good value
2 probably good value
3 probably bad value
4 bad value
5 changed value
6 value below detection
7 value in excess
8 interpolated value
9 missing value
A value phenomenon uncertain